I disagree with A&C regarding the extra costs after the 2000h mark.
My engine is around the 2500h TTSN and about 350h STO. It burns 1l of oil per 6.5h compression is between 74 and 78 on all cylinders. Every 25h I send oil for analysis and change it every 50h or 5 months.
Recently I had to remove 1 cylinder due to broken stud (the exhaust had to be removed), we have removed another one and had a good visual check.
The verdict was that I can keep running it for another 500h.
When the engine will have to come down (2000h or 20,000h) I want it to have new camshaft, new bearings, new pistons and cylinders, etc. I don’t believe in repolished camshafts and other corner cuttings.
Saying that, if I was in your shoes I would go for a new/overhauled engine. Put the insurance money into a good use.