The part of a bathroom remodel that decides whether it lasts is the part you'll never see again once it's tiled over. We waterproof the shower pan and walls before a single tile goes down, using a proper membrane system rather than relying on tile and grout alone to keep water out of the subfloor and the ceiling below.
Bad waterproofing shows up months or years later, not on day one. A shower that leaks slowly will crack grout, loosen tile, and eventually stain the ceiling of the room below, by which point the fix means tearing the shower back out. Vanities set on subfloor that was never checked for level will show a gap at the baseboard within a year.
When you're deciding on materials, ask about grout type for shower floors versus walls, and ask whether your exhaust fan is sized for the room, undersized ventilation is a common reason mold shows up behind tile in a house that otherwise looks fine. In a climate with Rockville's humid summers, a fan that actually clears the room after every shower matters more than most homeowners expect.