Repair shops repair entirely different kinds of things, so it's natural to assume they have specialists for each type. Oh sure, everyone there CAN do everything, but it's going to be a less-efficient job when the specialist is out to lunch.
It might seem it's a terrible idea to have the quality of a repair job be dependent on the time of day, but there can be advantages to this system as well.
Say you "stalk" the specialist and find out when and where they go on lunch break, you can talk to them while their boss isn't looking over their shoulder ready to take a cut of the repair fee. As such, if you catch a specialist on their own time, they could offer you a cheaper rate using their own personal tools. Additionally, they may drop that price even more if you own a set of tools they can use. The higher quality of the tools you have, the better they can repair.
Also, it might be unrealistic to expect them to repair stuff on their lunch break. However, you could simply use that time to set up appointments to meet them at their house or something for the repair job.
If they like you enough, they might be willing to set up a regular gig.