You won't regret investing in a set of ceramic thrust and diff balls, they last a
lot longer than the standard balls. In my experience when you're running all ceramic the entire diff wears less than standard parts, when the kit balls wear even a tiny bit they eat the diff/thrust rings very quickly. The Vampire ceramic balls are pretty much the same price as the standard AE carbide ones, I run all Vampire in my diffs.
Generally the diffs in my cars get a new set of diff rings every 3 months or so, the thrust washers get flipped and re-used at the 6 month mark and ceramic balls last the whole year easy
Regular cleaning and fresh grease make the AE diffs last much longer
