There are a number of different filters in your car, each designed to prevent debris from entering the vehicle's inner workings. They need to be changed periodically, as the buildup of debris can clog a system and render it useless or reduce performance. The major filters drivers should keep an eye on include the oil, fuel and cabin air filters. The recommended intervals for replacement of each can be found in the car's owner's manual, but drivers should visually inspect them every now and then between regular maintenance.
When too much dirt or debris gets stuck to the filter, it makes it difficult for the air, fuel or oil to pass through, which will adversely affect engine performance. Since they are designed to collect particles and need to be changed regularly, most filters are easy to remove, inspect and replace by hand.
There are two main air filters, the cabin air filter and the air intake filter for the engine. The air intake filter keeps debris out of your engine. If any outside particles find their way in, it could upset the combustion process or otherwise hinder the motor's ability to function.
Having a clean cabin air filter is equally important. This part is designed to remove pollutants from the air around the car to provide an improved air quality in the passenger cabin. It is also one of the trickier filters to reach on certain models. Some cars have access to the filter through the underside of the dashboard. If the cabin air filter is plugged up, it can cause the air conditioner to malfunction and affect the quality of air entering the passenger cabin.
While it may vary between different models, the general guidelines for replacing air filters suggest doing so roughly once a year. Since spring tends to come with lots of pollen in the air as flowers start blooming again, you may want to have a clean filter to keep as many of the particles out of your vehicle as possible, especially if you've got allergies.
Oil filters should be changed whenever you replace the fluid. The recommended intervals can be found in the owner's manual, but if you drive hard, or live in a climate with extreme temperatures this may need to be done more frequently.