What are you looking for by performing Air Duct Inspection?:
The first priority is to find air contaminants putting at risk the health of the residents:
Dirt, dust and dust mites
Mold, mildew other fungi
Drywall dust and particles
Pet hair and dander
I will explain whit down to earth words. You are using your lungs to breath and adding kislorod to all of your body sales. Duct system is the lungs of your house adding air to every room and every corner off your house. If your air duct system is contaminated whit Dirt, dust and dust mites, Pollen, Mold, mildew other fungi, Carpet fibers, Insect remains, Drywall dust and particles or Pet hair and dander so are your lungs.
I will go one more step whit the explanation of health risk you are putting your self and your family by berating contaminated air. I will pull the most conmen sample moving to new constructed house, building extension to existing house, finished your basement or renovating your kitchen. In all of those situations is involving sanding of drywall those small air contaminants are health hazard. The material of the drywall is very similar to the concrete as soon as you ad water will harden the same is happen when you breathe the air in house after construction, you inhale the small dried drywall particulars but as soon they reach your lungs they get moistened from your body and drywall dust become concrete in your body. Now I give you the simplest explanation it is up to you to choose from the two options you have to spend the rest of your life going from doctor to doctor from hospital to hospital trying to get rid of air contaminants from your body or simple air duct cleaning after construction.