The helmet is integral, so it's every time, no exceptions, will cancel a ride if I get somewhere without it, and won't ride with them as won't.

Why?

1. My first career was in the hospital business, and

2. I've eaten the pavement many times including once when my helmet bounced (with my brains safely nestled therein) three times before coming to rest. That one busted my shoulder and cracked a hip which to this day can predict bad weather and has left me vaguely asymmetrical. My brains are no more addled than they were pre-dump.