Originally Posted by
I-Like-To-Bike
How long is that?
Ya mean helmet styrofoam takes either less than a year, or more than a thousand years to degrade, but degradation is unlikely during the one to a thousand year time period?
I mean it's unlikely "that the foam breaks down and loses important strength over time." At least not on the time scales we'd be concerned about. Sure, it might break down in a few hundred years. Or a few thousand. Or a few million. Realistically, until a helmet is actually damaged, the styrofoam portion should be as effective (or ineffective) as it was when new. The glue and the plastic shell on the other hand, who knows. Maybe only a few decades.
I have an old helmet, about 20 years old, at my parents' house, left over from my mountain bike riding days. I was looking it over a few days ago, comparing it to a much newer helmet that has hardly been used. The plastic shell seems to be in similar shape to the newer helmet, not at all brittle, and everything is still holding together well. It gave me no reason to think it wouldn't be suitable for use if anyone felt the need to wear a helmet while riding their bike.