Naturally, air filters must be replaced if they become damaged. However, to ensure your car is running at its best, it is recommended that you replace your air filters every 12,000 to 15,000 miles (19,000 to 24,000 km). This interval should be shortened if you often drive in dusty conditions. It's best to review the maintenance schedule provided by your car manufacturer to get the proper replacement program.
Unfortunately, service manuals aren't always easy to find, or you may not know exactly how long it's been since you last changed the filter. As for fluids, the general rule is that the darker and more murky they are, the more likely they need to be changed. The proper operation of your engine depends on sufficient air being able to move through the air intake system, through the air cleaner, and into the fuel supply system. Not changing a dirty air filter can lead to a set of potential problems.
Dirty or damaged air filters reduce airflow to the engine, which changes the car's air-fuel balance. If you've driven more than 12,000-15,000 miles since the last time you changed your air filter, it's probably time to change it. A clean air filter is designed to capture dirt and debris from outside air, preventing them from reaching the combustion chamber and reducing the likelihood that you will receive a large repair bill. Keep in mind that if you are driving in a sandy or dusty area, you may need to change the filter more often than the recommended time for your vehicle.
The cabin air filter traps dust, pollen, hair, particles, pollution, exhaust fumes, animal waste (yes, animals like to live under the hood sometimes), basically all kinds of substances you don't want to get into your nose, mouth, and lungs. In today's typical cars or trucks, air filters may have a square, rectangular or trapezoidal shape - unlike in the old days when they had a thin circular shape that was prominently placed on top of the engine. It seems that every time I change my oil I'm told I need to replace basically everything else too. When it comes to changing your car's air filter it is important to remember that this is an essential part of regular maintenance. Not only will it help keep your engine running smoothly but it will also help keep you and your passengers safe from any harmful particles that could be entering your vehicle's cabin.
So make sure you check your car's manual for the recommended interval for changing your air filter and stick to it.