To maintain high air quality and ensure your system runs smoothly, replace your air filters every 90 days. If you have pets, allergies, or a busy household, consider changing them every 30–60 days. During peak seasons, check your filter monthly and replace it if it looks dirty. Homes with multiple pets or allergy sufferers might need replacements every 20–45 days. Regular filter changes help your HVAC system work efficiently, improve indoor air quality, and prevent issues.