Rick,
Here are some threads where this subject has been discussed before:
http://www.337skymaster.com/messages...light=overhaul
http://www.337skymaster.com/messages...light=overhaul
http://www.337skymaster.com/messages...light=overhaul
http://www.337skymaster.com/messages...light=overhaul
http://www.337skymaster.com/messages...light=overhaul
http://www.337skymaster.com/messages...light=overhaul
Everyone's opinion is different. One thing that I would consider is how many years old are the engines? If you have been running them 150+ hours per year since birth, making them about 10 years old right now, I would feel comfortable running them to the Seneca TBO, and in fact that was my plan on my airplane when I owned it. If they are 20 years old, on the other hand, I would overhaul them fairly soon.
The Air Force TBO is not really relevant to us. That was for airplanes that flew 2 to 3 times per day, 5 to 7 days a week. A 2000 hour engine in the Air Force could be barely six months old...
The one thing everyone agrees about is that these engines last longer the more frequently they are used...
Kevin