The general recommendation for replacing a car's engine air filter is every 12,000 to 30,000 miles, or about once a year, depending on your vehicle model, driving conditions, and manufacturer guidelines. For example, Ford suggests changing it every 15,000 to 30,000 miles, Chevrolet every 45,000 miles, and Hyundai recommends every 15,000 miles if driving on unpaved roads or in harsh environments

. Factors influencing replacement frequency:

• Driving conditions: Dusty, polluted, or high-traffic areas require more frequent changes, sometimes as often as every 6,000 miles.
• Driving habits: Frequent short trips or heavy towing can clog filters faster.
• Visual inspection: If the filter appears dirty or discolored (not white or grey), it should be replaced.
• Performance signs: Reduced acceleration, engine power loss, or black smoke from the exhaust can indicate a clogged air filter

Cabin air filters should typically be replaced every 12,000 to 30,000 miles or once a year, with more frequent changes in dusty or polluted areas or if you notice bad smells, reduced airflow, or allergy symptoms inside the car

. In summary, most drivers should replace their engine air filter roughly every 12,000 to 15,000 miles or annually under normal conditions, but this interval should be shortened in harsher environments or if symptoms of clogging appear

. Always consult your vehicle’s owner manual for manufacturer-specific recommendations.