What should a quote for an accessible shutoff valve replacement include?

An accessible fixture shutoff sounds straightforward, but the quote can depend on what’s assumed about the supply upstream and the connection at the fixture. Does the price usually assume the upstream shutoff works and can isolate the water?

I’d also want to know whether replacing the valve includes a new supply connector, or whether that’s priced separately. If corrosion or a damaged fitting means extra work once the valve is removed, is that typically handled as an added charge, and how should the estimate describe that possibility? I’m trying to compare scope, not pin down a price without knowing the details.