According to experts, changing filters on a regular basis may have more to do with your car's longevity than any other single factor.
Oil Filter: Oil filters are easy to replace and help prevent unnecessary engine wear. The job of the oil filter is to remove soot, rust particles and other solid contaminants from the oil. Oil filters should be replaced with engine oil every 3,000 miles.
Air Filter: Air filters remove dirt by trapping particles as air passes through the filter media. They also protect the carburetor in older cars, preventing dirt from clogging the air bleeds and metering jets. They protect fuel injectors in later-model autos.
Air filters should be replaced every 20,000 miles but more often if you live or drive in dusty areas. Any filter that looks heavily loaded should be replaced regardless of the number of miles, as should any filter which shows any type of damage.
PCV Breather Filter: The PCV breather filter assures only clean, filtered air is drawn in through the PCV breather. A clogged breather filter prevents the PCV from siphoning away the blowby gases and moisture created by engine combustion, resulting in oil breakdown and sludge buildup. The PCV breather filter should be replaced every 30,000 miles; however, yearly replacements are a good preventive measure.
Fuel Filter: Contaminants can get into your fuel system and if not trapped by the fuel filter, they can clog the injector inlet screens. If dirt reaches the injector itself, it can clog or damage the pintle valve and seat. In older cars, dirt can plug the carburetor's fuel metering orifices.
If the fuel filter is not replaced regularly, fuel flow to the engine will become restricted, resulting in stalling, loss of high speed power and hard starting. The fuel filter should be replaced every 30,000 miles; however, professionals recommend a yearly fuel filter change and a change whenever other fuel system parts are replaced.
Automatic Transmission Filter: Properly filtered transmission fluid transmits energy, plus it cools and lubricates the moving parts of the transmission.
A clogged transmission filter can produce transmission slippage, engagement problems and hesitation. Experts recommend this filter be changed every 12,000-15,000 miles to extend the life of your automatic transmission.