I get what Ginger is saying. I mean I have only rebuilt mine about every other year. But if your foxes were pitted on the shafts then that is straight forward to the cause of failure. Once they loose pressure (in your case you were loosing oil, so not loosing nitrogen volume but loosing oil thus dropping the pressure) they have to be rebuilt. I haven't had any problems with my rear shocks yet, but I have considered getting boots especially if I decide to drive it much in the winter with the crap on the road that will eat the shafts right off.