In our other house, I always had fully tiled so easy to keep clean with tile effect cushion floor. When we moved both ensuite and family bathrooms were tiled to shoulder height with beautiful Moorish looking blue/white/grey tiles and looked lovely. So I had the remaining walls and ceiling painted in brilliant white,I should add it is a dark house.
Now quite a few years down the line all are looking tired. I'm debating as well ,have the existing regrouted and the top third tiled in white or have the whole thing done completely. I must add that there is now a mark where tiles meet the wall due to condensation and dust they need cleaning each week.
The floor was non-slip grey tiles which look a bit industrial I can put up with that but the grout between just looks mucky and no amount of bleach will clean it.
I would say listen to what others have said I certainly have.