The frequency of air filter replacement depends on various factors, including filter type, system usage, and environmental conditions. As a general rule, fiberglass filters should be replaced every 1-3 months, while pleated filters can last 6-12 months. HEPA filters may need to be replaced every 12-24 months. It’s essential to monitor filter condition, airflow, and system performance to determine the optimal replacement schedule for your specific refrigeration system.