Imagine your car without the air conditioner compressor, air pump, alternator, cooling fan, power steering pump, water pump, and other accessories. That's exactly what you'll have if your serpentine belt snaps. So it's important to have it inspected regularly, and replaced according to your manufacturer's recommended schedule.
As part of the complete maintenance check you receive with every full-service oil change, we visually inspect your car's serpentine belt. If it has more than four cracks per inch in the ribbed section of the belt, and/or cracks that penetrate more than halfway through the thickness of the belt, it should be replaced.
Still, the serpentine belt's appearance doesn't always reveal whether it's on the verge of failure. Be sure to have it replaced on schedule - no matter how it looks. For most vehicles, this only takes about 10 to 15 minutes.