We don't use one, but I know some that do. I've got 17 hooks this year and only 1 break *knocks on wood*. Have replaced the R&P twice, once because I broke, and the other because there was a tiny chip off of one of the ring gear teeth. It probably would have been fine, but I decided to change it. Definitely going to pull the cover off and check it out before Scheid. Will probably put a new set in it just for good measure. We've set em up about every way you can think to try them, loose pinion preload, tight carrier preload, tight pinion preload, tight lash, loose lash, whatever... Seems like it doesn't make a lot of difference as to how long they last. What has seemed to help though is running a diff cover with load bolts for the main caps, and after I broke one of my 2nd main cap I went to a set of billet main caps.
FWIW I know of several pullers who just run setup bearings on the pinion to make swapping them out quicker.