Belts And Hoses are constantly exposed to heat, vibrations, and harmful chemicals.
As a result, that makes them vulnerable, to cracks and leaks.
Belts are used to hold the engine in time. And, help in the rotation of the camshaft, crankshaft and accessories. Hoses, support the flow of fluids, through the engine.
All belts and hoses need to be replaced, sooner or later. And, the cost to replace them is cheap, compared to the alternative.