How often to clean your ducts in your home you may be asking. Well it really depends on the conditions in your home. If your home is in a dusty area like near a dirt road or major freeway, then most likely you will need a duct cleaning every other year. Now if you live in a dust area plus you smoke and have indoor pets then you will be looking at every year.
The average person in an average home, if they keep up with changing filters and their air conditioning maintenance, will be looking at more like every 3 years.