I am lucky enough to have a second spare bedroom that would make a great dressing room but it is not adjacent to my room so could not be knocked through.
I don't have loads of house guests so wandering through the corridor in my underwear isn't an issue and worst case on those occasions, I could have an outfit ready for the morning in my room. Anybody done this and are there any downsides? I would still have a large chest of drawers and maybe a dressing table in my bedroom. Just no wardrobes.