Replying to Don't buy/sell used helmets

This is something that bothers me when I see it on this site. It's a safety issue.

I know some people here are just trying to make a buck, or save one. Just be cautious. All helmets are single impact only, any time after that, the risks of injury increase dramaticaly. The average lifespan of a helmet is 3 years. A hairline fracture is almost impossible to see with the naked eye, and though the high density styrofoam used to make helmets is very strong, it deteriorates like anything else through use.

Don't put a price on your head, or that of others.

In fact, if you know a helmet is no longer safe, destroy it before disposing of it.