We cleaned the ducts in the house we lived in before moving to The Villages. It removed a lots of dust and accumulated crud. My wife is allergic to dust and it made a big difference for her.
But the ducts in that house were the regular metal ones so I wasn't worried about damaging them. I've thought about cleaning our ducts here but I would need to be convinced that technique used to clean them would not damage them and be effective. The tools used in our previous house to clean the ducts would shred the ones we have here to pieces.
As far as dust goes we added a Carrier Infinity MERV 15 air filter to our AC here in The Villages. It made a difference for my wife and dust seems to collect inside the house more slowly now. The filters are more expensive for this system than standard ones but it does help if you have allergies to dust and such.
Air Purifier DGAPA