Engine air filters trap dust, pollen, and debris before it enters the engine. Over time they clog. Clogged filters reduce airflow, hurt fuel economy by 5-10%, and reduce engine power.
Typical replacement interval: 15,000-30,000 miles for engine air filters, 15,000-25,000 miles for cabin air filters (which clean air entering the HVAC system).
DIY replacement is genuinely easy on most vehicles. Open the air box, remove the old filter, drop in the new one, close the box. Total time: 10 minutes. Total cost: $15-$30.
Quick-lube places sometimes upsell air filter replacement at marked-up prices. Doing it yourself saves 50-70% on the parts cost.
Cabin filters are similarly easy on most modern cars — typically behind the glove box. Cleaner cabin air means better HVAC performance and cleaner air inside the vehicle.