I replaced mine after discovering excessive neg camber (tilting inwards) on my X5 with 100k. I first replaced upper control arm, then did the rear balljoint. I still have neg camber, just not as much.

I have a bottle jack with a 90 degree welded bar (about 10" )on top of it. I had it made for this purpose. As noted elsewhere, I jack up the spring perch (i have coil springs) to relieve pressure on rear wheel knuckle and then see if there is play in the wheel.

got the idea from this forum and the VAC youtube video