Actually, you don't have to log that many miles to break a crank. I broke some Campys and an Ofmega with fairly low mileage -- and some Campys with high mileage. Most recently, I was amazed to have broken a Shimano Ultegra triple with probably less than 10K (although it is hard to tell because it got switched around to a few different bikes). I was pretty impressed with the Japanese cranks until then. All you can do is watch for cracks, and for me, the failures have not been occurring at the pedal eye, so the Jobst fix (chamfered pedal hole, washers, etc.) would not have helped.-- Jay Beattie.
Wow. So where did yours fail? I have an Ultegra Triple that will probably hit 10k in the next year.