I don't believe in forcing other adults to wear helmets, I think it should be their choice. I will always wear a helmet though. 2 months ago I was cycling home from work in the rain going downhill and the car in front of me stopped short, which meant I had to stop short. Luckily I didn't hit the car, but I crashed pretty hard. The back of helmet had huge scrapes on it, but I was okay, pretty banged up and bruised, but I was okay. I just kept thinking how much worse those scrapes would have been on the back of my head rather than my helmet. I don't care if you or anyone else wears a helmet, but I will always wear one.