Do you not have any screens in your own bedroom? You don't text your friends or watch TV or Netflix etc, and see it as enjoyable/relaxation?
Times have changed. When your DC are teenagers your rules are going to be difficult to enforce. All my DCs' homework at secondary school is put up online and via an app. The vast majority of it is completed online and resources online such as BBC bitesize/mathswatch are used. Homework is usually emailed or printed out. Do you want your DCs doing this on a shared PC in one room, it just makes it so much harder!
Books are read on a Kindle Fire, technically a screen. Allowed in bedrooms.
Remember the days of talking to your friends on a landline in the hall? These days DC can group chat/text and multi task. If you (trust them) and can give them privacy why wouldn't you? Will they really have to go into the lounge/playroom to discuss what time they are all going to meet at Nando's on Saturday (which will take bloody hours, btw
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Mine don't watch programmes at set times on the TV, they stream favourite series and watch on their laptops, they like to lounge in their rooms to do this and why wouldn't they?
When they are older do you really think they won't have a TV or use their phones in their bedrooms? Of course they will and it's better, IMO to help them learn to regulate their use.
Your DC are lucky enough to have their own rooms, they will value their privacy and freedom not to have to fight over one remote, take advantage of it!
There are ways to still supervise and set limits, a timer for the WiFi and a password they have to "earn" if you like. Phones downstairs at bedtime etc.
Besides, when they are teens you may well be desperate for them to go to their rooms s guve you a break
There is only so many times you can listen to "OMG right Jane is such a snake, she was like totally chatting and I was like you what mate, you're totally extra and she was like..." without wanting to weep 