My rule is no helmet - no ride, with absolutely no exceptions. Even if I'm just riding round the block to check something, my helmet is securely strapped on. In fact my helmet goes on before I unlock my bike and only comes off when the bike is locked back up or away again, so I'm never actually on a bike without wearing head protection. That's a very strict routine I'm in after falling a few years ago and cracking my helmet. I fully realise a helmet won't save me in 100% of crashes, but I really can't see the logic in not wearing one. I'm convinced I've been very well protected by my helmet a few times in the past and I genuinely believe circumstances do exist where wearing one can save your life, which is why I think every single person who rides on two wheels NEEDS to wear one. It's just a shame not everyone does!