Replacing Your Helmet
Replace your helmet if it was involved in a crash; it probably absorbed
some impact shock. Some helmet manufacturers will inspect and,
when possible, repair a damaged helmet. If you drop your helmet and
think it might be damaged, take advantage of this service.
Most helmet manufacturers recommend replacing your helmet every
two to four years. If you notice any signs of damage before then,
replace it sooner.
Why replace your helmet every few years if it doesn't appear
damaged? Its protective qualities may deteriorate with time and
wear. The chin strap may fray or loosen at its attaching points; the
shell could be chipped or damaged. The best reason is that helmets
keep improving. Chances are that the helmet you buy in a couple of
years will be better - stronger, lighter, and more comfortable - than
the one you own now. It might even cost less!