From Clover Ledge Farm
*points to title*
The science backs it up. I really have nothing further to say on the matter.
Have I ridden without a helmet? Yes, but by far 99% of my time in the saddle is while wearing a helmet. If I fall off and hit with some part of the helmet it is immediately replaced. It's not something I will ever shortcut.
Plus, there's so many styles to fit heads and budgets.