This air filter element should be changed every 4,000 hours or at a minimum of once per year. Air filters should be changed on a more frequent basis If your compressor is located in a dusty environment or an area with lots of pollutants in the air. Proactively replacing the air filter prolongs the life of your compressor by protecting the critical parts on the inside of the compressor. This also increases your energy efficiency by not restricting the inlet airflow going into the air compressor.