Size

• Choose a helmet that matches your head circumference; measure above the eyebrows and compare to the manufacturer’s size chart.
• The helmet should feel snug but not painful. It should not rock back and forth or side to side when you shake your head.
• If a helmet has removable padding, use thicker pads for a tighter fit or thinner pads if it’s too tight.
• Replace any helmet that has been involved in a crash or that no longer fits—helmets degrade over time (typically replace every 3–5 years depending on material and use).

Positioning

• Sit the helmet level on your head: the front rim should sit about 1–2 finger-widths (roughly 1–2 cm) above your eyebrows to protect the forehead.
• The helmet should cover the top of the back of your head, not tilt too far forward or backward.
• Fasten the chin strap so it’s snug: you should be able to fit one or two fingers between the strap and your chin. The straps should form a “V” just below each ear.
• Do a final check: open your mouth wide—your helmet should press slightly down on the top of your head. If it lifts, tighten the straps or adjust the fit.

References: Consumer Product Safety Commission guidance; Snell and ASTM helmet fitting standards.

Follow the manufacturer’s instructions for cleaning and storage because different helmet materials and finishes require specific methods (e.g., mild soap and water only; avoid solvents, prolonged sun exposure, or extreme heat). Correct cleaning preserves the helmet’s protective liners, straps, and shell integrity. Store helmets in a cool, dry place away from direct sunlight and heavy objects that could deform the shell or compromise the foam.

Replace your helmet after the manufacturer’s recommended service life (commonly 3–10 years) because materials such as EPS foam and adhesives gradually degrade with time, exposure, and use. Also replace a helmet immediately after any significant impact, even if there is no visible damage, since the energy-absorbing structure can be compromised. Following these guidance points maintains the helmet’s ability to protect you effectively.

(See manufacturer manuals and standards such as CPSC, ASTM, or EN for model-specific recommendations.)

Choosing the right helmet and fitting it correctly matters because a helmet only protects when it stays in the right place and absorbs impact as designed. Here are short, concrete examples showing why each selection in your checklist is important:

• Certified for the activity

  • Example: A bike helmet certified to CPSC protects against the kinds of falls and speeds common in cycling; a skateboard helmet (ASTM) is built for repeated low-height impacts. Using the wrong-certified helmet can leave you vulnerable in the typical accidents of that activity.

• Fit to head shape and correct size

  • Example: A cyclist with a round head will get proper contact and stability from a round-shell helmet; an oval-head person may find the same model rocks back and forth and provides less protection.

• Level positioning (1–2 finger-widths above eyebrows)

  • Example: A helmet tipped too far back exposes the forehead; in a forward fall that can let your brow hit first and transfer force to your skull and brain.

• Snug internal fit system

  • Example: A helmet with a tightened dial and pads won’t slide off in a crash. If it’s loose, the helmet can shift on impact and miss the area that needs protection.

• Correct side-strap “V” and chin-strap tension

  • Example: If the side straps sit too high or the chin strap is too loose, a glancing impact or sudden stop can rotate the helmet off the head. With straps set properly, the helmet stays aligned over the skull.

• Retention and pull tests (open mouth, move helmet)

  • Example: When you open your mouth and feel the helmet pull down slightly, it indicates the chin strap and padding are keeping the helmet seated — the way it must behave in a collision.

• Replace after impact or service life

  • Example: A helmet that took a crash may have internal liner cracking you can’t see. Replacing it prevents reliance on compromised protection.

These examples show how each step reduces the chance that a helmet will miss, shift, or fail when you need it most. For detailed guidance, consult manufacturer fit instructions and safety bodies such as the U.S. Consumer Product Safety Commission (CPSC) or Snell Foundation.

Different helmet shells are molded with different internal shapes. A cyclist with a round head will get even contact around the circumference from a round-shell helmet, so the liner and straps press uniformly and the helmet stays stable during movement. An oval-head person fitted into that same round shell will have contact at only a few points, which lets the helmet rock forward/back or side-to-side and reduces the effectiveness of the energy‑absorbing liner and retention system. Conversely, an oval-shaped shell matches an oval head’s longer front‑to‑back profile, improving full-surface contact, comfort, and stability — all of which increase the helmet’s ability to stay properly positioned in a crash.

Sources: helmet fit guidance from CPSC and major manufacturers; helmet-safety standards (e.g., CPSC, Snell) discussing fit and retention.

The open-mouth and movement checks verify that the helmet’s retention system (straps, buckle, and internal fit system) is doing its job: keeping the helmet firmly seated on the skull so it can absorb and distribute impact forces.

• Open-mouth test: When you open your mouth wide and the helmet pulls down slightly, that shows the chin strap and internal padding are tensioned correctly. In a crash the helmet must stay low on the forehead and not lift off the head; this slight downward pull simulates the neck and jaw motion during sudden deceleration.

• Move-the-helmet test: Trying to shift the helmet front-to-back and side-to-side checks that the shell and liner are snug against the head. Only minimal movement is acceptable because excessive displacement means the helmet could rotate or slide in a collision, reducing its ability to protect the skull and brain.

Together these simple checks confirm the helmet will remain positioned to do its energy-absorbing work in an impact. (See CPSC and Snell fit guidance for the same basic procedures.)

A single impact can crush or fracture the helmet’s energy-absorbing materials (like EPS foam or other liners) in ways that aren’t visible from the outside. Once those materials have absorbed a crash force they may no longer compress properly in another event, so the helmet can’t protect you as designed. Likewise, over time adhesives, foams, straps, and shell materials degrade from heat, UV, sweat, and repeated use; that aging reduces protective performance even without a crash. Replacing a helmet after a significant impact or when the manufacturer’s recommended service life ends ensures you’re not relying on compromised components and preserves the helmet’s ability to absorb and dissipate crash energy.

Sources: CPSC helmet guidance; manufacturer manuals and standards (e.g., ASTM, EN).

When you open your mouth wide and the helmet pulls down slightly, that shows the chin strap, pads, and internal retention system are correctly positioned and tightened so the helmet stays seated on your head. In a collision the helmet must remain over the skull to absorb and redirect impact forces; if the helmet shifts upward or off the head, it cannot protect the most vulnerable areas. This simple test simulates the downward force that can occur during an impact and confirms the helmet will stay in place when needed. (See CPSC and Snell fit recommendations for the same verification.)

Placing the helmet level and about 1–2 finger-widths above the eyebrows ensures the helmet covers the forehead and the frontal bone — the parts of the skull most likely to take initial impact in a forward fall. If the helmet sits too high or tips back, the forehead is exposed and your brow or skull can strike first, concentrating force on a smaller area and increasing the risk of skull fracture, facial injury, or brain movement inside the skull.

Conversely, if the helmet is tilted too far forward it can block vision and ride down over the eyes in a crash, reducing your ability to see hazards and increasing the chance of the helmet shifting off the head. The 1–2 finger-width guideline balances protection and comfort so the helmet will stay positioned to absorb impacts as designed.

References: CPSC and Snell fit guidelines; manufacturer fitting instructions.

Different helmet certifications reflect testing for the typical forces, impact locations, and frequency of impacts associated with particular activities. For example:

• A bike helmet certified to CPSC is tested for the kinds of linear impacts and speeds common in cycling crashes, so its foam, shell, and retention system are optimized to absorb those forces.
• A skateboard/park helmet meeting ASTM standards is designed to withstand multiple low-height, repeated impacts (falls onto hard surfaces) without catastrophic loss of protection.

Using a helmet certified for a different activity can leave you vulnerable because its materials, construction, and testing focus on different impact patterns. A motorcycle helmet (DOT/Snell) is heavier and designed for higher‑energy impacts and abrasion at road speeds; it’s inappropriate for casual skate use because it’s overbuilt for small repeated knocks and may not protect against the typical lateral or rotational impacts a skateboarder faces. Conversely, a bike or skate helmet won’t provide the high‑energy protection or full‑face/abrasion resistance needed in a motorcycle crash.

Fit matters equally: even a correctly certified helmet cannot protect you if it sits too high, tilts, or has loose straps. Proper positioning, snug internal fit, and correctly adjusted straps ensure the helmet stays in place and the energy-absorbing liner performs as intended.

Sources: CPSC, ASTM/EN standards, Snell Foundation — see manufacturer fit guides and standard summaries for specific test criteria.

Different helmet standards test for different kinds of impacts and conditions. For example:

• A bike helmet certified to CPSC is designed and tested to absorb the higher-energy, glancing impacts and rotational forces typical of bicycle crashes at moderate speeds.
• A skateboard or multi-sport helmet meeting ASTM standards is built to withstand repeated, low-height, direct impacts common in skate parks.
• Motorcycle helmets certified to DOT or Snell are tested for much higher-speed impacts and offer greater coverage and structural strength.

Using a helmet certified for a different activity can leave you underprotected because its materials, internal liner thickness, shell construction, and test criteria target different impact energies, directions, and frequency. Fit and retention are equally important: even a correctly certified helmet won’t protect you if it sits too high, is loose, or the straps aren’t secured. Replace helmets after significant impacts or when they reach the manufacturer’s recommended service life to ensure reliable protection.

Sources: CPSC Bicycle Helmet Standard; ASTM F1492 (skateboarding); DOT FMVSS 218 and Snell motorcycle helmet standards.

A helmet with its internal fit system (dial or pads) tightened and the straps properly adjusted stays in the correct position on your head during normal use and in a crash. Because the helmet is snug, impact forces are absorbed by the helmet’s shell and foam rather than being transmitted through slippage to your skull. If the helmet is loose, it can rotate or shift on impact so that the energy misses the foam in the damaged zone and the vulnerable area of your head is unprotected. Proper strap placement (the “V” under each ear) and a secure chin strap keep the helmet from tipping forward or backward, ensuring the protective coverage stays over the forehead and temples when you need it most.

References: CPSC helmet fit guidance; Snell Foundation fit recommendations.

If the side straps sit too high or the chin strap is too loose, a glancing impact or sudden stop can let the helmet pivot or slide off your head. That rotation shifts the helmet’s energy‑absorbing foam away from the area of impact, reducing protection and increasing risk of head injury. When the straps form a snug “V” under each ear and the chin strap is tightened so only one–two fingers fit, the helmet remains aligned over the skull and transfers impact forces into the helmet shell and liner as designed, maximizing protection. (See CPSC and Snell fit guidance.)

A helmet that has been in a crash can suffer internal damage—such as microcracks or compression of the energy‑absorbing foam—that isn’t visible from the outside. Those hidden failures reduce the helmet’s ability to absorb impact forces in any future collision. Replacing the helmet removes the risk of relying on a compromised liner or shell and restores the designed level of protection. Manufacturers and safety standards therefore recommend immediate replacement after any significant impact. (See CPSC, Snell, ASTM/EN guidance.)

Helmet certification means the helmet has been tested against specific impact types, speeds, and test procedures that reflect common accidents in a particular activity. Different standards focus on different threats:

• Cycling (CPSC): tests for high-energy impacts typical of bicycle crashes and road speeds; shell and EPS foam are tuned to manage single, relatively large impacts at those speeds.
• Skateboard/roller sports (ASTM F1492): tests include repeated lower-height impacts and concentrated strikes (e.g., hitting curbs or hard edges), so liners and shells tolerate multiple knocks better.
• Motorcycling (DOT, Snell): designed for much higher-impact energies and often test rotational and penetration resistance plus full-head coverage.
• Snow sports (EN/ASTM for skiing): consider cold temperatures, different impact angles and surfaces found on snow and ice.

Using a helmet certified for a different activity can leave critical vulnerabilities: it may not absorb the right energy levels, may fail under repeated impacts, or may not cover the parts of the head most at risk. Always choose a helmet with the appropriate certification for your primary activity and follow the manufacturer’s guidance.

Sources: CPSC, ASTM, DOT/Snell, EN helmet standards and manufacturer fit guides.

A helmet with the internal fit system (dial and pads) tightened sits snugly on the head so it moves with you instead of sliding independently. In a crash, that snug fit keeps the helmet’s energy-absorbing shell and foam aligned with the part of the skull that needs protection. If the helmet is loose, it can shift or rotate on impact, so the force is not dispersed over the intended protective structures and vulnerable areas of the head may be exposed. Properly adjusted straps and a snug liner also reduce the chance the helmet will come off entirely during a high-force event.

Source: helmet fit guidance from CPSC/Snell manufacturer manuals (energy-absorbing liners must be correctly positioned to function as designed).

A helmet’s shell and internal padding are shaped to match common head profiles. A round-shell helmet is deeper and more evenly curved; it makes broad contact with a round-shaped skull, distributing pressure and keeping the helmet stable. An oval-shell helmet is narrower front-to-back and fuller side-to-side; it sits more closely on an oval head and resists rocking.

If the shell and liner don’t match your head shape, contact points are reduced and the helmet can tilt or rotate during normal movement or impact. That movement undermines the liner’s ability to absorb and spread force, so the helmet provides less reliable protection and feels less stable. Choosing a helmet whose shape matches your head ensures better contact, improved comfort, and optimal protective performance.

Sources: CPSC and helmet manufacturers’ fit guidance; Snell Foundation fit recommendations.

If the side straps sit too high or the chin strap is too loose, a glancing impact or sudden stop can let the helmet tilt or rotate off your head. That rotation can expose parts of the skull that the helmet should be covering and reduce the helmet’s ability to absorb and spread impact forces. When the straps are adjusted so the side “V” sits just below the earlobes and the chin strap is snug (one–two fingers’ space), the helmet is held firmly in place and stays aligned over the skull, allowing the shell and internal foam to do their intended job in a crash.

Sources: CPSC helmet fit guidance; Snell Foundation fit recommendations.

A helmet tipped too far back exposes the forehead; in a forward fall your brow can strike first, concentrating impact forces on a smaller area and allowing more force to transmit to the skull and brain. Conversely, a helmet positioned too far forward can obstruct vision and fail to protect the upper forehead and frontal bone in a frontal impact. If the helmet sits loosely or the chin strap is too slack, it can shift or come off during a crash, so the shell and energy-absorbing liner won’t be in the right place to absorb impact. Tight, level positioning keeps the helmet’s protective zones aligned with the most vulnerable parts of the head, spreads impact forces over a larger area, and ensures the liner compresses as designed to reduce transmitted force to the brain (CPSC; Snell Foundation).

Choosing a helmet that matches your head shape and correct size is essential because helmets are designed to absorb and distribute impact forces only when they sit snugly and evenly on the skull. A helmet that matches your head shape (round vs. oval) provides full contact across the shell and liner, preventing pressure points, gaps, or rocking. The right size — measured just above the eyebrows and tightened with the internal fit system — keeps the helmet level and stable during normal movement and in a crash. If the shell rocks, tilts, or shifts, the protective foam may not engage the head properly, increasing the risk of injury.

Example: A cyclist with a round head will get proper contact and stable fit from a round-shell helmet; an oval-headed cyclist wearing that same round model may experience rocking and reduced coverage, so an oval-shaped helmet will provide better stability and protection.

Sources: CPSC and Snell helmet fit guidance; manufacturer fit manuals.

The side straps should form a snug “V” that meets just below each earlobe and the chin strap should be tightened so only one or two fingers fit between strap and chin. This configuration keeps the helmet seated low and centered on the skull: the V anchors the helmet laterally so it cannot slide off to the sides, and the snug chin strap prevents forward or backward rotation. If the V sits too high or wide, or the chin strap is loose, a sudden stop or glancing blow can tip or shift the helmet, reducing coverage and the liner’s ability to absorb impact. Properly adjusted straps therefore maintain alignment and ensure the helmet’s protective structure is where it’s needed during a crash.

When you open your mouth wide and the helmet pulls down slightly, that shows the chin strap and internal fit system are correctly tensioning the helmet against your skull. In a crash the helmet must stay seated on the head so the shell and energy‑absorbing liner can distribute forces over the largest area and prevent excessive rotation or displacement. If the helmet moves independently (doesn’t pull down), the strap is too loose or the fit is poor — the helmet can shift or come off on impact, greatly reducing protection.

Source: basic helmet-fit guidance from CPSC and helmet manufacturers; see CPSC fit checks and manufacturer fit guides.

A helmet that was in a crash can have internal damage you cannot see — the energy-absorbing foam and adhesive layers can develop cracks, compression, or delamination even when the shell looks intact. Those hidden changes reduce the helmet’s ability to absorb impact energy in a future crash. Replacing the helmet removes the risk of relying on compromised protection and restores the designed level of safety for your head. (See CPSC, Snell, and manufacturer guidance recommending replacement after significant impact.)

A helmet tipped too far back exposes the forehead; in a forward fall your brow may strike first, concentrating impact on a smaller area and allowing force to transmit more directly to the skull and brain. Conversely, a helmet tilted too far forward can block vision and let the back of the head strike in a rearward fall. A properly leveled helmet covers the forehead (about 1–2 finger-widths above the eyebrows) and spreads impact forces across the shell and inner foam, reducing peak acceleration to the skull and brain and improving overall protection.

A snug internal fit system (dial, pads or liners tightened to the shape of your head) holds the helmet firmly in place so it stays aligned with the parts of the skull it’s meant to protect. Proper tension prevents the helmet from rotating, sliding, or coming off during sudden impacts; that ensures the energy-absorbing liner contacts the correct area and disperses force as designed. Too loose → excessive movement and reduced protection; too tight → discomfort and possible distraction. Aim for snugness that doesn’t cause pain but keeps the helmet from shifting when you shake your head.

Sources: CPSC helmet fit guidance; Snell Foundation fit recommendations.

A helmet should sit level on your head so its front edge is about 1–2 finger‑widths above your eyebrows. This position ensures the helmet covers the forehead (protecting the frontal bone and brain) rather than riding too far back, which leaves the forehead exposed, or tipping forward, which can block vision and shift protection away from the most vulnerable areas. A level, low fit also helps the helmet stay stable during movement or impact and allows the retention straps to hold it securely in place.

Not all heads are the same: some are rounder (equal front-to-back and side-to-side), others are more oval (longer front-to-back). A helmet that matches your head shape will sit evenly, distribute pressure correctly, and stay stable in a crash. If a helmet feels tight at one spot, or shifts easily when you move, it probably doesn’t match your shape. Try different brands and models—manufacturers use different internal shell shapes—until you find one that fits snugly without painful pressure and doesn’t rock when you shake your head. A proper fit improves comfort and, more importantly, safety.

Sources: Consumer Reports — helmet fit guidance; Snell Foundation helmet fit tips.

Ensure the helmet’s retention system (chin strap and any adjustable rear cradle) is fastened snugly so the helmet cannot lift or shift when you tug it side-to-side or front-to-back. The chin strap should sit low on the chin and allow one or two fingers’ space when closed. Also confirm the helmet fully covers the back of your head and the forehead—sits level, not tilted back—and that side straps form a “V” under each ear. Proper retention and coverage keep the helmet in place during an impact and protect the skull and brain effectively.

References: Consumer Product Safety Commission (CPSC) helmet fit guidelines; Snell Memorial Foundation helmet fitting tips.

The side straps should meet under each ear to form a neat “V” shape; the strap adjusters (sliders) should sit just below the earlobes. This positioning keeps the helmet stable on your head without pinching the ears: the V holds the helmet centered and prevents it from tilting forward or back, while sliders below the earlobes ensure the straps lie flat and can tighten evenly around the jaw. If the sliders are too high or low the straps can shift, reducing protection and causing discomfort.

Sources: U.S. Consumer Product Safety Commission, helmet fit guides; Bicycle Helmet Safety Institute.

Even if a helmet shows no visible cracks or dents after a crash or hard blow, its protective materials (foam liner, retention system) can be damaged internally and lose their ability to absorb future impacts. Helmets are designed to absorb one major impact by deforming; that deformation can be microscopic and not easily seen. Continuing to use a helmet that has experienced a significant impact risks reduced protection and greater chance of head injury in a subsequent crash. For safety, replace the helmet after any substantial impact, or follow the manufacturer’s guidance if they provide inspection and replacement criteria.

Sources: helmet safety guidance from organizations such as the U.S. Consumer Product Safety Commission (CPSC) and Snell Memorial Foundation.

Place a soft tape measure around your head just above the eyebrows and ears, where the helmet’s rim will sit. Keep the tape level and snug (not tight) and note the circumference in centimeters or inches. Compare that measurement to the helmet manufacturer’s size chart and choose the size that matches. A correct fit ensures the helmet sits level on the head, covers the forehead, and can be adjusted comfortably for safe protection.

Sources: Consumer Product Safety Commission — Bicycle Helmet Safety Standards; Snell Memorial Foundation helmet fitting guidelines.

With the straps fastened, open your mouth wide — the helmet should pull down slightly on your head. This quick test checks that the helmet sits low enough on your forehead and that the chin straps are snug. If the helmet does not tug down when you open wide, the straps are too loose or the helmet is sitting too high; tighten the chin straps and re-adjust the fit pads or helmet position until you feel a slight downward pull. A properly seated helmet stays stable in normal motion and will better protect your head in a crash.

Reference: Bicycle Helmet Safety Institute; Snell Memorial Foundation guidelines on helmet fit.

After placing the helmet on your head, tighten the internal fit system (the rear dial or internal pads) until the helmet feels snug but still comfortable. The goal is a secure fit that sits level on your head and does not shift when you shake your head. If the helmet moves independently—rocking forward, backward, or side-to-side—loosen or retighten the system and reposition the helmet until movement is eliminated. A properly adjusted fit system keeps the helmet stable in a crash and ensures the straps and shell sit where they provide protection.

Sources: Consumer Reports — Bicycle Helmet Fit; U.S. Consumer Product Safety Commission — Bicycle Helmets.

After placing the helmet on your head, adjust the fit so it sits level — not tilted back or forward — and low on your forehead (about two finger-widths above the eyebrows). Tighten the internal retention system (dial or pads) until the helmet feels snug but comfortable: it should not move independently when you shake your head. Adjust the side straps to form a “V” just below each ear and fasten the chin strap snugly so you can fit one or two fingers between the strap and your chin. Recheck that the helmet remains level and secure; a properly adjusted helmet stays in place during normal movement and in a light tug test.

References: Consumer Product Safety Commission, Bicycle Helmet Safety Guidelines; Snell Memorial Foundation helmet fit recommendations.

Different activities expose your head to different kinds of impacts and risks. Helmets are tested and certified to standards specific to those risks, so always use a helmet with the certification that matches your activity. For example:

• Cycling: look for CPSC (U.S.) or equivalent regional standards — designed for residual-speed falls and glancing impacts common in bike crashes.
• Sports (skateboarding, climbing, equestrian, etc.): choose helmets meeting ASTM or CE standards appropriate to that sport; these account for sport-specific impact patterns and coverage.
• Motorcycling: use helmets certified to DOT (U.S.), ECE (Europe), or Snell — built for higher-speed impacts and different penetration and retention demands.

Wearing a helmet with the proper certification ensures it was tested for the kinds of forces you’re likely to face, giving you the best protection for that activity. (For further detail, see certification agency websites: CPSC, ASTM International, DOT/NHTSA, Snell Memorial Foundation, ECE.)

Selecting the right helmet means matching protection, fit, and purpose. Pick a helmet certified to relevant safety standards (e.g., CPSC for U.S. bicycle helmets, ASTM for sports, DOT/ECE for motorcycle helmets). Choose the style designed for your activity (road cycling, mountain biking, skateboarding, motorcycling, climbing) because construction and coverage differ. Size the helmet using the manufacturer’s sizing chart: measure head circumference, try the helmet on, and ensure a snug but comfortable fit—it should sit level on the head (front edge about 1–2 finger-widths above the eyebrows), neither tilt back nor press excessively. Fasten the straps so the buckle rests under the chin and form a V-shape under each ear; you should be able to fit one or two fingers between the strap and chin. Check for proper retention and no excessive movement when you shake your head. Replace a helmet after a crash, visible damage, or according to manufacturer life guidelines (typically 3–10 years). For further reading on standards and fit, see CPSC Bicycle Helmet Standard and Snell Foundation guidelines.

Buckle the chin strap and tighten it until only one or two fingers can fit between the strap and your chin. This ensures the helmet stays securely in place during a crash: too loose and the helmet can shift or come off; too tight and it will be uncomfortable or distract you. The one- to two-finger rule balances security with comfort and allows normal jaw movement and breathing. (See NHTSA and helmet manufacturer fit guidelines.)

After tightening the straps and securing the chinstrap, test the helmet by attempting to move it front-to-back and side-to-side with your hands. A correctly fitted helmet should shift only a little — enough to feel snug but not so loose that it slides freely. Excessive movement means the helmet won’t stay over your head on impact and could expose your skull; too-tight movement indicates improper adjustment points (pads or straps) need tweaking. Aim for minimal movement: the helmet should stay centered and cover the forehead while allowing you to open your mouth comfortably. If you can easily rock it more than about an inch or it comes off when you tug, readjust or try a different size/model.

Reference: Consumer Reports and U.S. Consumer Product Safety Commission guidance on helmet fit and retention.

Regular maintenance keeps a helmet effective and safe. Clean the shell and inner padding with mild soap and water; avoid solvents, bleach, or strong detergents that can weaken materials. Wipe and let it air dry away from direct heat or sunlight. Check straps, buckles, and the retention system for fraying, cracks, or stiffness; replace any damaged parts if manufacturer replacements are available. Inspect the EPS foam liner and shell for dents, cracks, or compressions—any visible damage can compromise impact protection.

Replace your helmet after any significant impact, even if there’s no obvious damage, because energy-absorbing foam can be crushed internally. Also replace a helmet after 3–5 years of regular use (or sooner if the manufacturer recommends it), since materials degrade with time, sweat, UV exposure, and temperature cycles. Always follow the helmet maker’s care instructions and replace with a certified model that fits correctly.

References: Manufacturer care guides (e.g., Snell, ASTM, CPSC standards) and safety advice from road-safety organizations (e.g., NHTSA, RoSPA).