Ideas for use of DS's bedroom.

apparently ours are still 'their bedrooms'

A sauna or walk-in wardrobe sounds good.

My experience of kids at uni is they come and go frequently and sometimes bring a mate home to stay. The summer holiday is quite long - best part of three months. Ours have been fortunate enough to get summer jobs to boost their funds( or reduce the overdraught!)

Ruby bet it will still be full of DS stuff that he doesn't take with him.

In September go and sit in room (with window open there will still be the aroma of teenage boy).
You might then be able to feel what or how you would like to use the room In the future.

Isn't it still his room till he finishes university?

If you DID turn it into a sauna , as mentioned in your OP, where would your son sleep when he came home in the holidays?

Mine is the spare bedroom for visiting family I have my PC in there but to honest I barely us it anymore nowadays so it will probably be consigned to the loft and the room purely for visitors or overnights for the grandchildren.

Hope (silly hudl)

Ha, hollow laughter, my spare room has been turned into a walk in wardrobe with the added extra of another pantry/food store. All my DH's doing. Let's home we don't have any surprise overnight guests!

I might get a lodger in the future, but not just yet. I'm doing a Greta Garbo, "I want to be alone"