Comparing Apples to Apples
It is nearly impossible to compare apples to apples in the business of art and restoration. That is not what anyone wants to hear when they are planning a project, but it is important to bear in mind. Establishing a clearly defined scope of work, step by step; considering the intended materials and options—and gleaning an understanding of how long the work can be expected to last, with what level of disruption—all can help provide a more equal comparison.
Stained glass restoration provides a good example of how interpretations can vary, even for the same word. “Restoration” to some means completely replacing all the lead caming in a window, while to others, it means spot repairs. The spot repair price will be quite a bit lower but will have a short lifespan; while the re-leading will be more costly—but last for decades.
Even something as simple sounding as repainting a specified area may be quoted with more or less thorough preparation work planned, which again can mean years of difference in its longevity. Especially when the additional cost of scaffolding is involved, it is worth the effort to request clearly delineated proposals, ask questions, and determine what balance of options/costs/outcomes is best for you.