I had a little incident yesterday when I hit a patch of sand at around 20-25 mph, washed out front and rear, first thing that hit the ground was my face, or I should say my face shield at left eye, nose level, did not touch the helmet at all. I always ride with a full face helmet and always will. I can only imagine the face, head damage with a half helmet or even a 3/4 one. Of course I used to ride with no helmet, started riding in 1952...there were no helmets then, except WW 2 'tank' ones with holes in the top and a leather chin strap. Helmets may be hot and restrict vision, but I will always wear a full face.