Long and Son recommends regular Air Duct Cleaning for a residential home or business every 2-5 years, with air handler cleaning every year. These recommendations depend on the size of the HVAC system, age of the home and system, the amount of people and pets living in the space and whether occupants suffer from asthma or allergies. For older homes, homes with pets, or occupants with asthma or allergies, you should consider more frequent cleaning intervals.