There are degrees to what can be dealt with. For components that are not meant to be dissembled (like der parallelagrams, most unit BBs and crank spindle press fits as examples) then removal, cleaning and reinstalling is good. But bearing seals can be removed, caliper pivots unthreaded, pulley wheel bushings dissembled. Unit BBs can be removed from the shell and spindle. Posts removed. Interfacing surfaces cleaned and lubed before reassembly. All pivots spot lubed if not taken apart. And there's more of course.

What I do at work for paying customers is their choice. What I do for my self is my choice. I ride many years old stuff that was top grade in their time and now are still really nice. Tires, cables, rims (spokes w/ rims), chains, cogs/rings, tape, cleats get serviced but replaced as they wear out. Most all else gets strung along as long as the standard can work for me. Andy.