A makeover is a scope with a hard edge. Nothing behind a wall is touched and no drain, vent or supply line is relocated. Inside that edge there is more available than most people expect, and outside it there is nothing at all — which is why the useful conversation about a makeover happens before it starts, not on the morning something turns out to be soft.
What is genuinely achievable: paint, mirrors, lighting and hardware; a vanity swap of similar width onto the existing stops and waste; a new top on a sound carcass; a toilet swap where the rough-in distance matches, that being the measurement from the finished wall to the centre of the closet bolts, commonly 305mm but found at 254mm and 356mm in older island houses; a new extractor fitted into an existing housing and duct; re-grouting and re-sealing where the substrate behind is still sound.
Two things end a makeover more often than anything else. The first is a shower valve. Replacing a trim kit is a surface job only when the new trim fits the existing valve body, and across different manufacturers it almost never does — at which point the valve has to change, and the valve is behind the tile. The second is a vanity of a different size. Move to a narrower or wider cabinet and the wall behind it is unpainted, the floor beneath it may be untiled, and the shut-offs and waste arm are rarely where the new cabinet wants them.
Some popular shortcuts do not survive contact with a wet room. Coating tile inside a shower fails at the corners and the floor junction, usually within a couple of years, because those are the places that move and stay wet. There are signs, visible before anything is committed, that a room will not accept a surface-only scope: grout that has been renewed more than once, a tub-to-tile joint recaulked repeatedly, a floor that gives underfoot near the toilet, a wall that sounds hollow low in the shower.