Symptoms: An intensly annoying squeak every two seconds, cracks in the belts
A bad belt will usually be pretty easy to spot. You'll see the wear starting to fray and crack. Before you start ripping off your current belt, make sure you have a belt diagram or draw a belt diagram. You're going to want to know the path the belt takes. Once you've got this down, use a ratchet to loosen the tension arm, freeing the belt. With the pulleys exposed, make sure there is no excess rubber, grime or oil that would hasten belt disintegration. Use your diagram to reroute the new belt, lock up the tension arm, and you're ready to go.