I have a hardtime grabbing small nuts, so one of the times I was removing my tails, I dropped it and thought I busted it. Thankfully, I did not the bust the nut, and everything was okay. When changing tails, make sure you take the rubber from the one tail, and reapply it to the new one (only on some applications) . (yes you can reuse rubbers) That way when you put the nut back onto the tail, theres a rubber there too. Then, of course, theres no leakage that would cause any kind of failures.
Moral of the story: Wear a condom or your girlfriend will get pregnant.
scotty