Tile gets the compliments. Waterproofing decides whether you are still happy in year twenty. I build bathrooms from the substrate out, because water is patient and it always finds the shortcut somebody took.
A bathroom is the only room in a house that gets soaked on purpose several times a day. Everything about how it is built either respects that or ignores it. When I open up a failed shower, the story is almost always the same: no waterproofing membrane, a pan that does not slope to the drain, or tile set directly onto ordinary drywall in a wet zone.
None of that is visible on the day the job finishes. It shows up two or three years later as a soft spot in the hallway floor or a stain on a ceiling downstairs, and by then the repair costs multiples of what doing it right would have cost.
The other half of the job is the stuff nobody thinks about until they need it. Blocking in the walls so a grab bar can be added later without tearing out tile. A fan sized to the room and vented outside instead of into the attic. Enough light at the mirror to actually see your face.

Full removal down to framing, followed by an honest look at joists, subfloor, and any rot the last leak left behind.
Supply lines, drains, venting, and valve placement set before anything gets closed up and inspected.
Proper membranes, sloped pans, sealed corners, and a flood test on the pan before a single tile goes down.
Layout planned so cuts land where they belong, with movement joints where the material needs room to breathe.
An exhaust fan sized to the room and ducted outdoors, plus lighting that works for shaving, makeup, and midnight trips.
Vanities, toilets, and hardware installed level and solid, with blocking behind the walls for future grab bars.
Bathrooms give warnings long before they fail outright. Most homeowners notice these and assume they are cosmetic. They usually are not.
One of these on its own may be a simple fix. Two or three together usually mean water has been getting somewhere it should not, and the honest answer is to open it up and look.
Send photos of the shower, the floor, and the ceiling below it. Those three pictures tell me most of what I need to know about what you are really dealing with.