I typically do not do repairs, but I do sometimes take on restoration work. For me a restoration is taking something that is no longer playable or structurally damaged and bringing it back to 100% playability and structurally sound.
I have restored a few special instruments over the years and it is always something tricky to get involved with. It is usually very time consuming and can be quite expensive so it is easy to get into a situation where the cost of the work can exceed the retail value of the instrument. Restorations can sometimes be more of an emotional decision than a sound financial decision. It is best to talk through a project like this before work begins so everyone is clear about what to expect.
That being said if I take in a restoration project, I generally price it up front so the customer knows what they are going to spend and I will not to exceed that amount without discussing it with the customer first. If we get into something unforeseen, I generally will fix it without adding any extra charges. Here are some pictures of some of the things I have done over the years.