Your cabin air filter should be changed every 12,000 to 15,000 miles, depending on driving conditions. A dirty air filter can decrease air quality inside your car and lead to respiratory issues, particularly for allergy sufferers. Additionally, it can reduce the efficiency of your heating and air conditioning systems. If you frequently drive in dusty or polluted areas, consider checking the filter more often. Clean filters not only improve air quality but also contribute to better fuel efficiency.