Is there like a notable warning prior to that happening? Is it only due to time, or is it mostly due to heavier use?
Although I haven't spent a lot of time messing with mine, I have kept the oil changed within the recommended parameters, and as far as use goes, I am rarely even in 4WD.
In addition to that the previous owners rarely ever used it in 4X4, in fact they were going to use in the sand once and the light didn't work and they never bothered to get it fixed, even though they kept immaculate maintenance records it was never mentioned, even though they paid top dollar having the AC updated to the newer compressor in roughly 2002