Filters have a efficiency rating called MERV, ( Minimum Efficiency Reporting Value). The higher the MERV rating , the cleaner the air and the better the equipment protection. Control dust, dirt, and pollen with high quality filters and/or air cleaners.
A typical maintenance check-up should include tightening all electrical connections and measure voltage and current on motors. Faulty electrical connections can cause unsafe operation of your system and reduce the life of major components.