A full gut-and-rebuild of a standard bathroom runs 2 to 4 weeks of work once materials are on hand, and 4 to 6 with custom tile and glass. The schedule's honest enemies are material lead times and inspection windows, which is why the written schedule starts when materials land.
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A full bathroom remodel is a parade of trades through the smallest room in the house, and the sequence is what sets the calendar. Demo takes a day or two. Rough-in plumbing and electrical (moving the drain for a new shower footprint, a fan circuit, valve replacement) takes several days and ends in a rough inspection where the city has one. Then the build-back: backer board, waterproofing, and tile, where the real time lives, because tile work is sequential (set, cure, grout, seal) and a custom shower with niches and a mud pan is craftsmanship measured in days, not hours. Vanity, counters, fixtures, and trim follow, and a frameless glass shower enclosure adds its own wrinkle: it is measured only after tile is done, then fabricated, which puts its installation a week or two behind the tile no matter who is scheduling. That is the difference between the 2-to-4-week standard remodel and the 4-to-6-week custom one, and it is also why the materials conversation happens before demo, not during: tile, vanity, and fixtures sitting in the garage on day one is the single biggest schedule protector. The written scope here includes the sequence and the schedule, the milestones payments tie to, and the honest note that a house's surprises (rot under an old pan, a slab-moved drain line) are priced as written change orders, not absorbed into vague days.