Atwood screw type leveler jacks

Have replaced 4 Atwood Levelegs, both rear and the driver's side front 2 times. Best way to keep them running is keep the weight on the tires, not tires off the ground. They are for leveling only not for changing a tire or service, which is why two of ours failed within a couple of cycles because the tires were lifted off the ground by service people. Two were changed under warranty and two I paid for. Of course they never failed before I paid the bill, always after and 500 miles away.