The helmet issue is not very complicated for me. I always just strap it on.
In the last 14 months, I've "crash tested" two helmets. I can report to you that both times, the helmets successfully prevented
a skull fracture.
I do have a few problems with helmets, though:
1) I always worry if it's on straight. Almost nothing looks funnier than a crooked helmet.
2) If I happen to climb into the car with it on, I always smack it against the door frame.

3) Crashing with one on can leave weird looking markings on your head.
4) If I strap my helmet over my glasses, it makes them crooked, which looks even funnier than a crooked helmet.
5) What if I lose
all my hair and forget my bandana? I've heard of "pattern baldness," but, "pattern sunburn?"
6) Helmets ruin some of your most potentially amazing stories, like, "Yeah, and see this scar? That's where they put in a titanium plate! My insurance covered the whole thing...go ahead, whack it with your finger one time."
7) Styrofoam is contibuting to the hole in the ozone layer (and I also feel funny spending 50 bucks for a chunk of styrofoam--at least it's cool
looking styrofoam...)
Well, I guess I'm off to buy another spanky new helmet!