You can tell a lot about a shop by what it refuses to do. Honest restoration is as much about what I won't do as what I will, and I turn down work regularly.
The lines I won't cross
I won't fake age. Distressing a new piece to look old, forcing a patina to counterfeit years a piece never lived, selling a reproduction as an original, that's forgery, and I don't do it. If a piece is new, I say so. I won't over-restore. There's a point where fixing a piece turns into rebuilding it, and if bringing a fixture back means replacing so much that little original is left, I won't then sell it to you as a restored antique. I won't do unsafe work, or teach it. I won't ship a fixture I wouldn't hang in my own house, and I won't publish a how-to for the electrical or finishing work that could get someone hurt. And I won't claim what I can't know. I won't invent a documented history for a piece to make a sale, won't tell you a fixture came from somewhere I can't stand behind, won't dress up a general story as a certified one. What I know, I'll tell you. What I don't, I'll say I don't.
These aren't rules I advertise to seem principled. They're just where the work stops being honest, and I'd rather turn down a job than do the dishonest version of it. Knowing what I won't do is how you know what my yes is worth.
Salvager's Note: The things a shop refuses tell you what its promises are worth. Faking age, over-restoring, unsafe work, invented histories, if a seller won't do those, then "restored," "original," and "safe" mean something when they say them.