Hmm???

Pedals are sealed now a days.

Hubs area sealed too, well the ones that use sealed bearings, if you have ball bearings in your wheels probably u have issues setting up the cones but pretty much if the wheel is ok and the cones are ok u dont need to adjust them maybe each 5 or 10 years.

Headsets use sealed bearings, they need to be adjusted to take the play off the fork, even with motorcycles u have to do the same.

etc???