Anecdotes, research data seem to support both sides. Again, I see wearing or not wearing a helmet simply a matter of choice, and neither side should have to justify their choice.

I choose to because I feel a bit more insurance - remember, I have head-first crashed 3 times (both at speed and at no speed). Things happen fast, I ride sort of fast and the roads can be hazardous. Note, I have also fallen without moving, so it is not just a speed thing.

I know some hate seat belts, I have worn a belt for so long it feels too weird not too. What's funny? I often buckle up to move the car from the driveway to the curb, just because it feels too odd not too, not because I'm safer.

So, if you wear one, cool, if you don't, cool, if you do sometimes but not others, that's okay too. I do support kids wearing one, because they do not have the reaction skills should something happen (I'm sure some do, but in general, likely not).