The belts and hoses have to be in good shape in order for your vehicle to function the way that it should. There are two types of belts, which are the timing belt and serpentine belt. The timing belt is made out of rubber. It ensures that the camshaft and crankshaft are synched up properly. The timing belt is outside of the engine. The serpentine belt sends power to other parts of your vehicle such as the power steering pump, cooling fan and air conditioner compressor.
Timing belts typically last about 100,000 miles. The serpentine belt usually only lasts 50,000 miles. The hoses are what connect to the power steering, radiator, fuel lines, vacuum lines and heater. There are also some parts of the hoses that are connected to the engine. Most hoses have to be replaced after 50,000 miles.