Just like every material matter the oil has an economical life as you can imagine.After driving your car for long especially longer than the recommended time for oil change due to the high temperatures in the engine the oil stat loosing its viscosity and lubricating feature and that means bad times for your engine.

Same thing applies for the oil filter since there is a lot of friction inside the engine basically metal is grinding against another metal so they get overheated, tiny pieces are chipped away during this metal to metal touch and grind/ friction process and thanks to the oil's lubricating power this is prevented to very high extend but still some small pieces of metal will chip away and fall to the bottom of the engine carter or oil pan where the oil pump circulating the oil will run these small metal pieces through the oil filter where they will be retained in the filter so they don't cause any damage to the engine.

That is why it is recommended and it is vital to change your engine oil and oil filter on time especially if you are expecting your car engine to serve you for long time.