I go onto those jobs looking to make some money. The customer gets exactly what they wanted, which is new devices and plates, usually decora white for this type of job. Just about every single time there are a few hang ups not for every outlet, but some just like Charlie pointed out. Or the box is too small for all the wires in there, or something. So I flat rate the whole thing at level difficult and if they get price shock, well thats the rate folks take it or leave it. My price is usually about 60% of brand new house wiring outlet per. Upsize boxes are on my dime but- I make it plain in my contract proposal that if I have to run any new cable its more. If there is no ground wire present and its not full size- more. Aluminum?- more. Existing hack add ons - more. Not uncommon to remove a plate and find some zip cord double lugged onto the terminal screws running off in the wall someplace- Fixing that = more. I say at least very minimum is 55 or 60 bucks an oultet. Think Like MR. Electric and Thrive.