I have never worn one, i guess just cause of the comfort/warmth of a beanie vs the lack of each with a helmet. I coud be wrong but those are my reasons.
I have also thought a long time about the over confidence one gets when putting a helmet on. Do kids try things they wouldnt or maybe shouldnt when they have a helmet on? I know i have too much confidence already and dont need to have anymore. Obviously wearing a helmet is good most of the time, but if it has you doing things that you wouldnt normally try, just because you feel safer wearing one, then i am not sure its a good idea.
yeah i would do usually
but if im doing urban i will take it off time to time