with mtn biking, you might as well resign yourself to things breaking. The important part of this is when it happens ON THE TRAIL ( and it will) what are you going to do about it?
I've seen
-broken seat post
-derailleurs broken off
-broken chains
-chains sucked so hard that you can't get them out
-brake levers snapped off ( try riding 5 miles downhill with just a front brake sometime, this one was me)
It helps to ride with someone that has McGuyver like tendencies.:)

