Out of interest, isn't there (as with cars) a wide spectrum of practices in aircraft resprays?
For example, to do it properly they need to strip off all electrics from the wings. Remove all fittings, inspection covers, etc. Then rub down to bare metal. Then alochrome (or something like that) to restore the aluminium skin surface oxide.
I can see a lot of people skipping a lot of this. Especially paint around rivets, which you can't really ever remove fully, short of chemical stripping but you don't want to do that.
It's obvious that a proper respray is going to be a massive job. Everything has to come out so you have just an empty shell.