I always wear my helmet. The way i see it is that nobody ever plans to fall, and as much as we would like to think so, you cant anticipate a fall untill it is already happening. I even wear my helmet while just going from place to place, because if i do get hit by one of the drivers that is never looking, i would like to be able to survive. As my mom has always said "once your hit, it doesnt matter whos fault it is. Everyone else's life will go on, but YOU have to deal with the injury".
Also, wearing a helmet is not that big of a hassle. If you look around and get the right fit, after the first day you wont even know its there.
my friend was riding through town and was hit by a car, and he wasn't wearing a helmet, but he came out of it fine. But once he got to the docters, the docter said that the way he was hit, if he was wearing a helmet he could have been killed. So in this case a helmet could have killed him, pretty crazy if you ask me.
I rode DH for a while with just a pisspot, then smashed my face. Now if im riding dh, i dont even try with out my troylee, i losee confidence without it.
As for street or park i wear a pisspot, concrete is harder than my head.
You should wear a helmet just to ride becuase maybe youll have a car accident. I always wear ir. For DH I wear fullface and for street I wear a normal mtb one.
I live in vancouver canada and here it's illegal to ride a bike without a helmet but cops don't really care, I've never worn a helmet once to ride around town. When I'm dirt jumping, skatepark, trail etc I always wear a helmet. Although I can't stand full face I hate the visibility.