I have replaced 8 sets of these over the last 3 years on 3 different XJ6's.
2 90's an a 93
Nothing abnormal though. Each car had over 150k miles.

Besides the play you can feel in the wheel with the car up on a jack, they all have had a signature telltale. A hum while driving. Many mistake this hum for a tire issue. Make no mistake about it, it's bearings. It starts with a slight hum when driving between 60 and 70mph. As it gets worse you will notice it at lower speeds. Next time your out driving, have a listen. If you hear humming while your driving and it's not you, time to change your wheel bearings.