Start at the panel and work outward. Before anyone prices a panel job, stand in front of the box and look at the space around it. Electrical codes set a clear working zone in front of the panel, and the installer will measure it first. If a water heater, a workbench, or stored boxes sit inside that zone, something has to move before the work begins. Moving it is labor, and labor is part of the bill.
Where the panel sits
A panel on an open basement wall costs less to reach than one in a closet that opens onto finished rooms. Ask where the wall is finished. Plaster, paneling, and drywall behave differently when they have to be opened, and a repair patch is a line item someone has to name. Ask whether the new box can stay on the same wall or needs to move, because a move means new feeder wire through framing you have not seen yet.
The route in and out
Look at where the service wire enters the house and where the meter sits. The distance between the meter, the panel, and any outside equipment sets the length and type of wire. A long run through an attic or a crawlspace adds time, and a route that crosses a fire wall or a masonry chimney adds a step. Ask the installer to walk that route with you before you accept any estimate that assumes it is simple.
Capacity and the circuits
The size of the existing service and the loads the household now runs are the two things that drive the capacity conversation. A new heat pump, an electric range, or an added workshop can push the existing service past what is reasonable to keep. Each added load can mean added circuits, new breakers, and relabeled branches. Ask which loads the job is sized for and whether that list matches what you actually plan to run.
Utility, permit, and inspection
Some panel changes need the utility to disconnect and reconnect service, and some need a permit and an inspection before the power is restored. Those steps carry their own costs and waiting time, and they do not show up in the labor. Ask who schedules the utility visit, who pulls the permit, and whether the estimate says who pays for each.
What to ask before you compare
Ask where the new panel will sit and what has to move to make room. Ask who opens the wall and who closes it. Ask how the route for the new wire was checked. Ask which loads the capacity assumes. When two estimates differ, line up their assumptions first. A lower total can hide a route that was never walked.
The published figures and the planning window for this equipment are on the Electrical Panel page. Use that page for age and timing, and use this walk-through to decide what the site is asking for.