Dear Faith and Tim*,
We commit to a number of days to finish your project. This is a contract term. We also create and update a project schedule. The project schedule is not a contract term. It is a tool for us to manage your project.
Our often updated schedule, for example, will show when we rough-in the plumbing, mechanical, and electrical systems, the expected duration of that work, the overlap between trade partners, and our preferred sequence of work. Completion of prerequisites, trade partner availability, inspections, and material availability will all push and pull on that schedule, and we'll adapt as appropriate. All of this will happen and change with the big picture completion goal in mind.
The number of days to complete your project can change by change order or budget update. For example, if you make a scope change request, that may change the time required to complete the project. Material availability may also alter the time needed to complete the project.
P.S. I can't imagine scheduling and coordinating three successful co-headlining tours. Did you use a Gantt Chart? Or iCal? What about snow days? I have so many questions!
*Full disclosure: not only have we never worked for Faith Hill or Tim McGraw, we've never actually met them. Indeed, I'm not sure we've ever been in the same city at the same time. They seem like fun people, though, and we would be happy to build a home for them. If any of you are close friends with them, we would be grateful for an introduction!