We bought a new 128 when I was 12 or 13 to replace the #12 we had, the 128 got the Massey belt type thrower attached.
This unit was extremely reliable for the next 10 years I lived at home and used it, and another 12-15 years after that. The only thing I ever remember breaking was cracking on the extended hitch you need to use to get the tongue past the thrower, and that was after 8 or 9 years of very high usage. Could run 1000 to 1800 bales a day through it, and it never broke a sweat.
Keep the shear on the plunger set up to correct tolerances, and have the knotter assembly checked if misses any knots. Which is just about never if it is set up anywhere close to right.
One hopes it has been stored inside, if not, I would emery cloth any surface rust from the knotter assembly parts.
Used this on a 165 MF for the first few years, then a MF 283. Probably representative of the ideal HP range for this baler. (50 to 75 ish)
Ran between 10 000 and 20 000 bales or more a year through this unit, and it never let us down, ever. Every 2 or 3 years Dad thought it a prudent investment to pay for a couple of hours of shop time to keep the knotter set up.
Shop time in February is a lot cheaper than a field service tech in June.....:)
Nothing but good experiences with a 128.
If you only used it for hobby farmer level of baling, you would probably not have to do anything to it for 20 years or more of service.
Of course that depends on whether the original owner was good to it or not.