Flying helmets
Had to wear flying helmets and in a previous life and it was something that we didn't even think about. It was compulsory so that was that. I now fly training helicopters primarily and sometimes wear a helmet. If I am doing sightseeing where there is a constant change of passengers I usually don't wear one, more to interact with the punters than for any other reason.
I think there is no argument that helmets save lives and give you a much better chance when it all goes wrong. I also think you should wear a nomex suit and gloves but we don't always do that, do we?