I have always heard 3 years of racing. I do know of 1 guy that his gave up suddenly, but don’t know how much time was on it. I honestly don’t know if it gave any warning signs, but it was mid race and he seemed pretty shocked.
I had an oil fill plug come out and didn’t know until I hit the scales. I had about an ounce of oil left in it. I just re-filled it and ran it. What else could I do? So far so good.
Get a magnetic drain plug, safety wire your fill plug, use good oil and change it is about all you can do. If you run in the rain, at least check the oil if not change it.
It would be nice buy a new engine complete and keep it as a spare. You can always use the older one on non race weekend if you want to go through the engine swaps, even if you cut the seal and rebuild it. Then you have a bunch of redundancy on spares like ignition, carb and such but you end wanting a mount and pipe to make it easy to swap.
If money is an issue don’t worry and just run it and get some reasonable spare parts.
That is the beauty of the LO206