How often should I replace the filter in a pet household air purifier?

With pets, HEPA filters need replacement every six to nine months instead of the standard 12 months. Pet hair and dander clog filters faster, reducing airflow and efficiency. Pre filters (the washable mesh layer) should be cleaned every two to four weeks to extend the HEPA filter lifespan. Activated carbon filters for odor control typically last three to six months with pets.