I remove each wheel and hub, inspect the brakes, including linings, magnets, wiring and drums. Then, I remove the grease seals, clean and inspect the bearings and repack the bearings with new grease. I follow this up with new double lip grease seals and then install the hub with the proper bearing pre-load. When it's all installed, I finish off with a brake adjustment.
Now that's just what I do every
two years. The brake adjustment, I do once a year at the start of our camping season. We put 4-6 thousand miles on our camper annually.