Wilbur Bud

I've been riding these daily for a few years, just noticed mileage has passed 25,000. No complaints, just curious if there is anything I should be doing to make them last longer? When I ask at LBS they are willing to do a clean and adjust (my understanding is you don't really clean and lube the shielded cartridge bearings, but it is possible to do a thrust adjustment), but they also say sometimes they are just never the same once you open them up. WI tech support instructions say hubs will last longer with regular maintenance, but I've never understood what is regular maintenance.