You should replace the air filter in your car once a year or every 15,000 to 20,000 miles, whichever comes first. Consult your owner’s manual for a more specific estimate.
That said, how often you should replace your car’s air filter largely depends on your driving habits and the conditions you are regularly driving in. If you are someone who lives and drives in a drier, dustier, or sandier locale, you may need to replace your air filter more frequently.
For this reason, you have your air filter inspected at regular intervals throughout the year to ensure that it does not become clogged or oversaturated with particulate matter.