It should survive active duty for 50,000 to 100,000 miles without replacement. It might be a good idea to have it replaced if you notice scratches, cracks, or frays on it. In addition, an abnormally sounding engine might also be a good reason to have it inspected. The final sign it being about to breathe its last is poor function of the components it links. In any case, we advise you to replace it as scheduled. Failure to do so may result in greater expenses later on.