What does a serpentine belt do?

Well, it won't keep your pants up, but it does transport power to your vital automotive components. The serpentine belt is one long, snaking, winding belt that keeps your alternator, power steering pump, air conditioning and—in some cases—your water pump running smoothly and effectively.

Didn't cars used to have more than one belt?

Back in the day, cars had individual belts for many components. Though each belt could be replaced individually, these cars experienced inconsistent or compromised performance as individual belts began to wear down. 

Now that vehicles employ a single belt—the serpentine belt—that's no longer an issue. That said, it's critical that regular inspections are done to make sure the belt is in good shape.

How often does a serpentine belt need to be replaced?

Serpentine belts are built to last—much longer than before because of advancements in rubber technology. Under ideal conditions, a belt should stick with you for an average of 60,000 to 100,000 miles. 

Pretty impressive. However, some belts are manually tensioned and may need to be adjusted. Others have a self-tensioning mechanism that can experience wear over time and may need to be serviced. One thing to remember: in most cases, if the belt breaks, the vehicle will stop running.