Bearings do not go bad like clicking a light switch. They go bad over time...
I repack the bearings every year or two and check seals. When I travel, at the first stop after driving for a hundred miles or so, I check to see if the hubs are running cool, or just luke warm (and not hot to the touch).
I carry replacement bearings, grease and tools needed to change the bearings on the road.... but, I like to not have to do it on the road, so try to avoid it.
While your note might be helpful, most probably would be much better to do the right work at home to avoid having to do it on the road. With a lot less hassle.