Invest in a cheap cable tester like the Behringer or the like. If you're in a band, it's a necessity, but it's great for checking out your cables BEFORE you miss out on something because of problems.
Every so often I take a little time and go through my whole taping, recording, and live sound rigs with the tester.
Of course, it's also a great way to make sure the cables you just built are going to work after all!
Chuck