I wouldn't claim for a tiny prang. You lose your no claims and then your premium is going to go up. In the long term it's more damaging. I see the problem though. Why go fully comp if you're not going to claim? Well I'd only ever go fully comp if it's a decent car and I'd only ever claim if the damage is going to be substancial to my wallet.

Anyway, what do I know? I've never owned my own car because simply I can't afford the insurance anyway.