An essential part of car engine efficiency is the drive belt. Apart from its role in driving multiple peripheral devices in an engine such as the alternator, the water pump and the power steering pump, a good quality car drive belt creates less friction in the engine which gives your car an overall better performance.
Due to frictional forces, heat accumulation deteriorates the drive belt over time and can sometimes be diagnosed as a "squealing" noise from the engine compartment. Quality is important for a car drive belt, as if it snaps then your car will break down.