How many of you have a backup/second camera of some sort? I was originally thinking about renting a backup, but it will be more cost effective in the long run to buy used or refurbished.
Depending on the situation, I may throw an old body in my bag just in case. But that is not a hard and fast rule.
Ditto. I don't specifically bring a second body all times for that purpose, but sometimes bring one for fun...or if I expect rain a lot while I'm there I may bring a fixed-lens sealed body camera along as the 'rain' camera.