Hi everyone, I know where you can learn more about air ducts, especially in the case of allergies or pets, I recommend checking out https://comfortclean.com/how-often-should-you-clean-your-ducts-why-air-duct-cleaning-is-an-important-for-a-clean-home/ about how often to clean ducts. There you will find useful information and recommendations on how often to clean and how it affects the air quality in your home. This site explains the importance of regularly cleaning your air ducts and will help you understand how to avoid problems with air pollution and allergies.