How long should I go on engines?

[Rickskymaster]

I have 1200 hours SFReMan's on both engines.
Just came out of annual with no problems, using a quart of oil every 10 hours.
The question I am starting to think about is how long should I go before Overhauling them.
I have heard that the Air Force went 2,000 hours and then changed.
What is really confusing is the TBO. My recommended TBO is 1400 hours, yet the same turbo charged engine on a Seneca gets 1,800 hours TBO.
My thought right now is to run them to 2,000 and continue oil analysis.
Thoughts?
Rick