How often should you change your HVAC filter?
Every 3 months.
How to do it
Check the filter monthly and change it when it looks dirty, at least every 3 months. Note the size printed on its edge, and fit the new one with the airflow arrow pointing toward the unit.
Why it matters
A clogged filter makes the system work harder, costs more to run and shortens its life.
Recommended interval: every 3 months, per ENERGY STAR (U.S. EPA).
General guidance for a typical home; the manufacturer's instructions come first.