Don’t get black taps or funny shaped taps if you have hard water
If you want antique brass, rose gold or other non standard finish, check you can find everything in that finish first
Large tiles on floor and in shower = less grubby grout
Avoid natural stone anywhere that’s going to get wet a lot
Two sets of lights- one bright and one low - and/or a dimmer
Override switch so you don’t have noisy fan on during relaxing bath or at night
Electric underfloor heating if your bathroom gets arctic - costs a fair bit to run but put it on a timer, you’ll only use it at key times/months
Storage storage storage. Build it in to any funny little gaps. It will get used.
Niche in shower
Controls on a non shower wall so they are reachable without getting your arm wet
Make sure the floor is properly waterproof eg Ditra matting under the tiles and/or wediboard/marine ply as the base
Don’t choose a loo with a “poo shelf”
If you build in the cistern, make sure the cistern is accessible for repairs - ideally not just through the flush plate but have eg a removable shelf on top of cistern box
Wall hung loo and sink/vanity makes cleaning easier and room feel bigger.
Consider where you’ll put things like loo roll holder, loo brush, hand towel
If you’re eyeing up fancy stone baths, consider weight and floor strength
Ideally, don’t buy a bath without sitting in it in a showroom first, especially if it’s a non traditional shape
If bath will be used for kids, consider a bath filler rather than taps to avoid injuries
Waterfall showers are a bit rubbish unless you have a pump or naturally great water pressure (rare in the UK)
Hand held shower attachment is very useful for rinsing hair well and cleaning the shower/bath
Use eggshell paint on the walls and ceiling, it’s much better with moisture than emulsion