Replacing your air filter regularly not only keeps the air cleaner, but it may also be an easy way to upgrade car performance. You should change your air filter once a year or every 12,000 miles, or as recommended in the vehicle’s owner’s manual. Replacing your filter is a simple and quick DIY project that may contribute to better gas mileage and longer engine life and performance. To help ensure you replace your filter properly, consult your owner’s manual. If you’re not confident in your ability to do so safely, take your vehicle to a professional.