How often do AC ducts need to be replaced? Most people I know replace the AC pumps periodically but I've never heard of anyone needing ducts changed at the same time.
It depends on what has gotten in there and done any damage. My friends have just had to get theirs repaired because an opossum had taken up residence beneath their house. Animals can do some damage to duct work. Keep the critters out.
It depends on the condition of your AC duct. some would last up to more than 20 years. Just keep the habit of cleaning and inspection to prevent damage and early detection.
Our AC runs through the same duct work as our furnace. Now that I need a new heating system for the house, I plan to have our ducts cleaned out professionally, but they look and work just like they did 40 years ago.
Any one with experience in geothermal? That's what we are checking on to replace our dead fuel oil furnace.
We always used the serviceman who installed our AC for the few repairs it needed through the years. Now it's available if someone wants it in South-est, central-est Wisconsin.