On average your should change your air filter every 1-3 months. But how often you need to change your AC filter depends on the kind of household you live in. You need to change it more frequently if you have pets or if anyone in your home suffers from allergies. Your filter affects your indoor air quality and also the efficiency of your air conditioner.
It’s better to err on the side of changing too often. Once every 30 days is a good frequency. Pair a filter change with expert maintenance, and your air conditioner will be in top shape.