I have to wear one at all times when riding at the ranch I belong to, except for during shows I wear a cowboy hat, and when I occasionally take my mare off ranch property for trail rides or camping, I usually choose not to wear one. If I was riding a younger horse or one I'm not as familiar with I'd probably wear one. Like other people said, I don't care if people do or don't wear one, ITS THEIR HEAD! But what I do care about is when people try to shove their views on it down your throat..like when riding with 'helmeted' people who continually talk you down for not wearing one. That makes me want to quit riding with them, not get off and put a helmet on!
"Don't flatter yourself cowboy..I was lookin at your horse."