Started out never wearing a helmet as most didn't back in the good ole days. When I purchased my horses and brought them home, my non riding husband insisted that I always wear a helmet. I do not make promises that I can't keep, so now I wear a helmet. I do ride alone most of the time anyway so was a good idea. Took a while to get used to but now it's just part of my tack.
Funny thing is I never preach to other people about wearing a helmet, but they who do not wear one always feel a need to explain why they aren't wearing one. Makes me chuckle. I guess it's kinda like cussing around a priest, minister , nun ect.... feeling the need to be pardoned.