I bought our car with about 153,000kms on it. Wheel bearings had been replaced at 150,000km.

Since then I have checked & repacked them at around 165,000kms, & 203,000kms. On both those occasions there has been no noticeable play in the bearings.
Last week I checked for play again (230,000kms) & found the passenger side to have noticeable play, & the driver side had some play, but less than the passenger side.

Because I'm having issues with a bad back I paid for a local mechanic shop to check the bearings & either re-pack them or replace them with bearings I have been carrying with us today.

I got the car back with the bearings having been examined, re-packed & readjusted. They had determined that my new bearings weren't required.

Knowing now that the bearings were still good, I could have just adjusted them without re-packing, but of course it would have left doubts gnawing away at me If I'd done that.

Soooo....... I know the bearings were good 27,000kms ago, & have checked the wheels for play a couple of times since then & found none, & surmise that the play/wear I discovered recently has most likely occurred
in just the past 10,000 kms, most of which has been a mix of dusty corrugated roads & low range 4wd'ing.

I have no option other than to trust the judgement of the mechanics (having told them of our plans to be driving around Cape York for several months), although it is fair to say that had I been doing the job myself I would have erred on the side of caution & replaced them even if they had felt & looked ok.

So really my question is ..... If next time I again do the job myself ..........If the rollers in the cage spin without any graunchinness (after cleaning), & no scoring or ridging on the cups can be felt with a fingernail, no visual damage, & no 'blueing' from overheating will they still be ok to repack. For play to have developed there must have been wear, but if the wear is even & smooth - how does one know whether to replace them.

As I said I'll probably replace them anyway ..... but would like to know if there is any way to know whether they have reached their 'wear limit' in the absence of damage?