Fixture selection, piping, access, permits, inspections, and finishes need one coordinated sequence.
The short answer
Document the existing room, proposed fixture locations, product requirements, and who controls the property. Ask a licensed plumber to join the plan before walls are closed or cabinets and equipment are ordered. Confirm current permit and inspection requirements with the responsible professionals and the Town.
What to notice
Start with use and fit
Record the people and activities the room must support, then check fixture dimensions, clearances, connections, drainage, water delivery, and maintenance access. A product image or nominal width does not prove fit. Ask who verifies compatibility and what can still change after concealed conditions are exposed.
Sequence decisions around inspection
Identify demolition, rough plumbing, electrical or gas work, inspection, wall closure, cabinetry, waterproofing, fixture installation, and finish repair. Ask which work must remain visible for inspection. A schedule that ignores dependencies can create rework even when each trade’s individual task is correct.
Control changes in writing
Existing piping may differ from records or assumptions. Define how a concealed condition is documented, priced, and approved. Keep allowances separate from firm prices, and identify owner-supplied products. The final package should include applicable permit and inspection records, product information, warranties, and revised plumbing-map notes.
One useful question
Can a contractor decide permits after work begins?
Permit and inspection planning belongs before regulated work and before required conditions are concealed. Ask the licensed plumber and Town about the actual scope early. Do not assume that a designer, retailer, or general estimate has resolved plumbing requirements.