Looking After Your Visor: Cleaning And Replacement
Neither format is a universal answer. Weather, speed, journey length and personal comfort all play a part, and many riders end up owning one of each for different trips.
Trying a helmet on in person, and wearing it for a few minutes rather than a few seconds, catches problems a size chart alone cannot. Padding also settles slightly with use, so a helmet that feels snug when new is usually the right call.
Visors are a wear item, not a lifetime part of the helmet, and most riders find a spare on hand is worth having, especially before a long trip.
A clean visor is a safety item as much as a comfort one, since scratches and haze scatter light and make it harder to judge distance in low sun or at night. Clean a visor with lukewarm water and a soft cloth, and avoid dry wiping, linked internet page which is what causes most fine scratches in the first place.
Any impact, including a helmet dropped from a moderate height, can compress the inner liner in ways that are not visible from outside. A helmet is designed to absorb one significant impact by sacrificing that inner material, so a helmet involved in a crash should always be replaced, not inspected and reused.
A certified helmet carries a label inside the shell showing the standard it meets, along with a homologation number that identifies the specific model tested. This label is worth checking on any helmet, since it confirms the exact helmet in your hands passed the test, not just the range it belongs to.