Going to start meeting with contractors for bids on a master bathroom renovation. We have plans drawn up and approved and have identified our fixtures, etc.

Curious what sort of things we should ask about in order to be well informed. Here's the list of things that immediately come to mind:

Timeline (when they would start, how long projected)
What other projects they will have running simultaneously
Plans for use of subcontractors (anything specifically we need to clarify about subs?)
What about change order process - how does that work?
Will head guy be running the job, always on site?

What else, or what other tips would you offer to first-timers like us?