I always wear a helmet-whether road or trail riding. Always wore one when I motorcycled also. On my off-road bicycle, I've heard a helmet hit the ground more than a few times. Was always very glad I could get up and ride away! One off-road crash in particular, I know I would not have ridden away from if it had not been for the helmet--was dazed, but no concussion, luckily! I don't ever want to hear (or not hear) my head hit the pavement or dirt, rock, whatever.