This is speculation by me based on what Elon said at the annual shareholder meeting about servicing, but I would infer that this may be the model that Tesla is aspiring to regarding car servicing.
There may be one to three regional service centers per metro area (depending on the number of cars in the area). If you opt in and have your car report it's status back to HQ on a regular basis, Tesla will be able to monitor many items in the car and have reports when there are faults or potential issues with the car. They may even contact you proactively to let you know that your car is reporting some potential maintenance issue and that it should be serviced. With the information, Tesla will be able to preposition the parts needed for a repair through a just-in-time inventory type system, which improves efficiency and response time.
For most items, you will not drop off your car at the service center, you will let Tesla know where your car will be that day and they will come will come by and pick up your car and trailer it in a trailer that might look something like this:
it will be 'invisible service' because as far as you are concerned, you don't change anything about your day or schedule (assuming you have the kind of job where you go to the office and stay there the whole day without the need for a car). If you do need a car, you may be able to request one from Tesla and they will bring the car over for you to use during the day while your car is at the service center
This totally eliminates the hassle of going to the service center, waiting around, arranging a ride from friends/family, getting a loaner car etc. You can just go to the office and tell Tesla to pick up your car at the office, or you can stay home for the day and do stuff at home while Tesla comes to get your car.
If Tesla finds that the car will need an extended period of work, they will let you know and drop off another car for you to use for the time period your car is at the service center. Now you may say, wow isn't that going to be expensive and resource intensive? From a cost perspective Elon indicated that this model is actually much more efficient than the traditional service setup at dealers today. You don't need 'service advisors' and the efficiency gained by having less part inventory and better initial diagnostic information most likley is meaningful.
He used the example of how Enterprise Rent-a-car makes their business model work well even with their door-to-door service. Also the prepositioning of parts and having the insight into what may be going on with the car because of the reporting it is doing back to HQ improves efficiency from a parts inventory standpoint and a time wated diagnosing the issue standpoint.
Now what happens as Tesla scales up and has more and more cars out there? Time will tell if they can scale up this service model, but with electric cars theoretically the mechanical issues should be much simpler to deal with and the cars should require much less general maintenance (Elon made a comment at the meeting that even Internal Combustion Engine cars are way over serviced today because that is where the dealers make much of their profit), so most general issues should be quick service fix issues and the amount of cars at the service center should be proportionaly much lower as a percentage of the outstanding fleet compared to regular internal combustion engines. I think it will be a fantastic service model if Tesla really ends up implementing it. I for one will not miss waiting at the dealer, or taking time out of my morning to drive to the service center, wait for a shuttle to work and then have to leave work early to catch the shuttle back to the dealer.
Again, this is my speculation based on what I've heard, if it does come to fruition, it would be a revolutionary improvement in the whole servicing aspect of owning an automobile.