For optimal air quality and system performance, replace your air filters every 90 days. If you have pets, allergies, or a high-occupancy home, consider changing them every 30–60 days. During peak seasons, check your filter monthly and replace it if it appears dirty. Homes with multiple pets or allergy sufferers may need replacements every 20–45 days. Regular filter changes ensure efficient operation, better indoor air quality, and reduce the risk of HVAC issues.