A bathroom used by four people at speed, every day, wears out differently from one used twice a week. The failures are predictable: grout at the shower entry where wet feet land, the sealant joint along the tub, cabinet doors whose bottom edge sits in the splash zone. PVC-edged panel swells at any edge not properly sealed, and nothing brings it back. Drawers survive a family better than doors, because soft-close runners absorb what a hinge eventually racks. Mid-tone floor grout is a maintenance decision wearing an aesthetic disguise.
Temperature control is the specification most often skipped. A tank is kept hot enough to suppress bacterial growth, which is hotter than anything should arrive at a tap, so protection has to happen downstream — a tempering valve at the tank, plus a shower valve that holds temperature rather than merely balancing pressure when a toilet is flushed elsewhere. A thermostatic valve carries a limit stop, set once and left. The tub filler is the one people forget, and it is the outlet a small child is most likely sitting under.
Storage in a shared bathroom is not a volume problem, it is a separation problem. One deep cupboard becomes a place where things go to die. Divided drawers, one per person, a tall unit rather than a wide one where floor space is short, and a mirrored cabinet — the only storage in the room that is genuinely at eye level. A niche sized for what a family keeps in a shower rather than for two bottles, set at the reach of the tallest user.
A tub is the right call while children are small, and it is worth knowing what it costs afterwards. An alcove tub takes the room's best 1500mm wall, which usually pushes the shower over the tub — stepping over a 400mm wall onto a curved surface, behind a screen with a permanent junction to seal. Where the room can hold both separately, that is the better answer. Where it cannot, the question is which decade the room is being built for.