It is true that the AW hub is super reliable and never seems to wear out. An oil bath may smooth up the shifting, but I have seen hubs that needed a tear down and clean up before they would shift smoothly. If left un-oiled for a long time, surface rust can build up and cause a gritty feel and slow to engage shifting. The bike I'm working on now is totally frozen. The hub free wheels and the pawls engage, but the key doesn't budge in the axle slot.