How long does a serpentine belt last?
“Drive belts are designed to last for between 50,000 miles and 100,000 miles”
Haynes recommends that you look over the serpentine drive belt every time you change the oil. If this serpentine belt fails it typically isn't catastrophic, but your car will quickly overheat after a few miles without the water pump turning. You should plan on changing the belt every five years or 60,000 miles even if it looks okay. Replacements are inexpensive and typically require only a few minutes to change.
Find info on checking the belt here - Checking the Drive Belt
All cars are slightly different, so if it is time to change your drive belt, use our before you begin checklist, and find your car for specific instructions.