The frequency of cleaning or replacing HVAC filters depends on various factors, including the type of filter, the presence of pets, and household conditions. Generally, disposable filters should be replaced every 1-3 months. Homes with pets, smokers, or allergy sufferers may require more frequent changes, possibly monthly. Washable filters should be cleaned every 1-2 months. Regular maintenance ensures optimal airflow, improves indoor air quality, and enhances system efficiency. Always refer to the manufacturer's recommendations for your specific HVAC system.