Originally Posted by
merlinextraligh
No one actually knows, given that there isn't data available.
Most helmet manufacturers have recommendations to replace every 5 years or so.
What is known is that helmets have gotten better over time, and it's likely that even an inexpensive helmet is going to be lighter, cooler, more comfortable, easier to adjust than your 10 year old helmet.
Thus it would make sense to get anew one.
I have been pondering the same thing. I have an 8 year old helmet that I am giving to a friend who just started riding and has no helmet . I know he probably won't go out and buy one for himself, so I figure this is better than nothing. It's in good shape and has not been crashed, and I'd like his head to be in the same condition.