I bought a '99 Case 9010B with 12k hours, and doing more or less the same thing as you except that I will use my machine for most of the work on my property build and anticipate putting a thousand hours or more on it. It has some issues with bogging under load, which is a fuel related issue and is my work for sunday to repair. I am far from an expert, as I am a machinist, not a heavy equipment tech, but am tooled and capable to perform service work, and have been obsessively researching to understand hydraulic diagnosis with the assumption I will have failures on the machine. Knowing the pump, swing motor, and final drives are all $10k components, I was not willing to buy something already having hydraulic issues as that would be the heaviest cost and the things I had the least experience with.
Unfortunately any older machine is a risk of an expensive failure, and if you have to call in service techs for repairs it can get out of hand real quick. I personally chose to hold out for a machine that did not already have hydraulic issues. Mine has some electrical stuff to sort out, is missing some cab windows, and the fuel issue but those are right up my alley as far as being able to deal with. Tough to find older ones that arent relatively neglected, but they are out there. Hoping that by the time I am done with mine, after all of the service work and care, that I should be able to turn a profit on it when I sell it.
Good luck with the search, its a tough one to be disciplined and not buy yourself a liability.