Mine had to be replaced at less than 10,000 but I'm also sittin on 44's which arent very good for ball joints. Wish they still put kingppins in the front end instead of balljoints. But anyway had mine replaced with Moog parts and those have zerk fittiings so they can be greased. I've got just over 39,000 on the new ones and they still seem to be fine so far.