It may not make sense but I do wear a helmet when out on hard rides but not consistently when I putter around going to lunch, an short errands, etc. Every other type of ride on road or mountain I wear a helmet.

I know, I know, those short rides may actually be less safe but, well, that's what I do.

I know from personal experience, both my own and seeing first-hand the effects of a head hitting the pavement that a helmet can be the only thing standing between us the rider and a crippling injury or death. Both cases me and another rider were wearing a helmet and a chunk was taken out of the helment yet I and the other guy walked away. If we weren't wearing a helment, well, for me, I wouldn't be typing this. It's as simple as that.