Hmm. Just bought a cycling helmet for my last short tour which
encompassed quite a bit of city cycling. Never wore one before : don't
think I will again.

The added noise and irritation that the helment causes more than offsets
the "possible" help it gives in case of a spill by deducting from my
usual spacial awareness.

I don't know. I still refuse to believe that the helmet won't help in a
spill, but wonder if the %chance of it helping offsets the % increase
in likelihood of an accident due to lower awareness levels.