Quote Originally Posted by anthonykay View Post
Despite my neuroses, serious failures have actually been very rare for me. A catastrophic failure of a bottom bracket did once prevent me getting to a fell race, but I don't recall ever having a chain breaking. Having hub gears greatly reduces the likelihood of failures in the transmission, but the downside is that it can be a faff removing and replacing the wheel when a puncture occurs. Since getting a Shimano Alfine 8 hub for my Hetchins, I haven't had a puncture, but although the diagrams make it look easy, I am not looking forward to my first experience of getting the wheel off and back on with that.
It is very, very unlikely that you will break a chain when using a hub gear transmission, as the chain line is straight; it's the chain running at an angle that causes problems.

I would recommend, however, that you have a practice run of taking off, and putting back, your rear wheel. If I was in your position I would make sure I'd done it at home in dry conditions, so I knew what tools and techniques were required, before venturing away from home.