crashtech
Combo Man & Mod
Well, if you are doing work on a set bid, in insurance work, extra work needed is called a "supplement," in construction it's called a "change order." Just simply say, "that's work above and beyond what was quoted, and we'll have to charge for it" as you get out your clipboard.
Edit: Also, the more detailed your estimates are, the less free stuff you can be credibly talked into giving away.
Edit: Also, the more detailed your estimates are, the less free stuff you can be credibly talked into giving away.