This thread has been a fascinating read. I never wore a helmet as a kid, and crashed a lot while trying a lot of silly stuff. As an adult, I wear one every time I ride. I don't necessarily wear one because it's going to help in a severe crash (i.e. high speed or car / bike impact) because it seems like that much trauma would be more than the helmet is designed for, I wear one because even as an adult I still do silly stuff, and I'd hate to suffer a head injury because I forgot how to kick my foot out of my clipless pedals (which has happened a couple times already )