In fact he said he'd prefer not to tangle with bearings as he's had experince where even with all his tools and knowledge they've ended up whining and had to be re-done.

Then he is incompetent. Sorry, but if a mechanic cannot do a basic bearing repack, he needs to seek out some continuing education so he can figure it out. Packing bearings is something that I would not hesitate to run out and do right now. It is easy and never a bad idea as part of some sort of maintience schedule.

That said, I have a feeling your friend either cut corners (some smaller bearings and/or abused vehicles probably should replace the bearings as good measure) or he did not fully inspect the bearings (or mixed them up and put them with the wrong cones) and they either made noise or failed. Actually, if they were making noise, they did fail.

I also suspect that he does not have the slightest clue how hefty the Isuzu bearings are. They are HUGE. I am also not sure where the "Don't fix it if it isn't broke" mentality comes from. I guess he prefers to wait until they seize and take out the hub and spindle and leave you by the side of the road. It really is a much better bit of advice for his pocketbook.

That said, just do it. Take it apart. Keep everything in order. Clean all the old grease out of the bearings and the hub. Don't forget a new wheel seal on the back of the hub (but only after you put the repacked bearing in the hub). Pack those bearings very very very well with new grease (seriously, push grease until you think you have it and then push some more through). Put it all back together. Tighen that nut down, spin the hub to distribute the grease. Back it off. Tighten it until it is set with a pull-type scale and be on your way.

Good Luck,
Michael