Servicing is the basic building blocks that everything else is built on. If you know what oil and quantity a g-box holds and where to find the oil etc. When you go to rebuild a gearbox you already know one step.
Henry ford revolutionised car manufacturing with the assembly line. The task of assembling a car was broken down into 84 steps. A technician performing the same step over and over soon becomes very good at that one step.
Working on an assembly line on the same step for too long would drive you bat shit crazy. If you were able to master a step in the assembly line then move onto another step, then another step, and another step. Soon you will have mastered assembling a whole car. You will have learnt how to do it without costing efficiency and productivity because when the task is broken down into smaller specialised tasks it doesn't take long to be up to speed, performing the task quickly and efficiently.
Note: Previous tasks need to be revisited so you don't forget what you have learned
Think of servicing as your first step in the assembly line. Master it. Then move on to repair tasks