I agree with rogerstg, I've never had a bolt shear, approximately 12,000 loaded miles on two bikes (total). I did not appreciate the benefit of fenders for quite awhile. Depending on your fender stays and rack configuration, the fender stays may need to go on first. My wife's and my touring bikes both require this. I carry exra bolts, but never had to use them. I believe more trouble is casused when they loosen up so I check them regularily while on tour.