Both jobs took an afternoon. Both involved sucking everything through the ducts, then inspecting every vent, then spraying an enzyme (cherry scented!) that would eat all the organic material that the vacuum couldn't suck. I went ahead and paid for the heat/AC maintenance as we were just moving in and I wanted to be sure everything was working well from day one.
The Pepsi can and the coffee can lid in one of our floor heat duct explained why my son's room never warmed up in the winter! Lots of pet hair had formed with those two items to make a nearly perfect clog. (I'll go on and on if I don't stop myself now! *Bad* memories!!)
Thanks again for the information. I can only imagine what lurkes in my ducts!