Anti fog inserts and coatings help in cold or wet conditions, but they are not a substitute for a visor in good condition. Once scratches build up to the point where they catch the light on every ride, it is time to replace rather than keep cleaning around the problem.
Most manufacturers recommend replacing a motorcycle helmet every five to seven years even without a crash, since the internal materials that absorb impact degrade slowly with heat, sweat and UV exposure. The shell can look fine while the protective layer underneath has already lost some of its effectiveness.
Daily wear also plays a part. Sweat, sunscreen and regular use all shorten a helmet's working life, so riders who use a helmet every day should expect to replace it sooner than someone who rides occasionally.
From there, the build follows the same certified construction as the standard range. Made to order does not mean a shortcut around testing, it means the standard process is carried out around one person's measurements and preferences instead of a general size run.
For helmet care products and guidance, see
full face helmet.
Getting helmet sizing right starts with a proper head measurement, taken with a soft tape around the largest part of the head, just above the eyebrows and ears. That figure points to a starting size, but it is only a starting point, since head shape varies as much as head size.