For households with pets, filters should be changed every 60 days or two months. However, this interval can range from 20-45 days for those with allergies or respiratory issues. On the other hand, for vacation homes or those that get little use, it is generally okay to wait around 9-12 months before exchanging air filters. In general, more frequent use means needing to replace your filter more often. Call us at (626) 217-0559 and schedule a free consultation!