Air duct cleaning is an important part of maintaining the air quality in your home. Air ducts tend to get contaminated with dust, dirt, and dander, which can cause allergies and respiratory problems. This can be aggravated with regular use of air conditioning, making it all the more critical to ensure you are regularly cleaning your ducts. 

That really depends on several factors. If you live in a dusty climate where pollen levels in the air are particularly high, or if you have pets that shed a lot of fur, then you should consider getting your air ducts cleaned more frequently than the average homeowner - perhaps every year or two.