You should replace your AC filters every 1 to 3 months, depending on various factors such as usage, indoor air quality, and specific household conditions. Homes with pets, smokers, or individuals with allergies may require monthly changes, while homes in cleaner environments or with less frequent AC use might extend this to every three months. Regular inspections and timely replacements when filters appear dirty ensure optimal airflow, enhance efficiency, and maintain better indoor air quality, contributing to the longevity and performance of your AC unit.