@ariadne @whitequark Tbh, I'm not a fan of that either. If your child is using computers all day, there's probably a reason for that. If you set a limit, you don't solve the issue but just mitigate the symptoms.
e.g., I had few friends and was bullied.
When my parents limited my screentime, I just read books instead. At some point they had taken everything, and I'd just spend the afternoons in my own mind and dreams. When they forced me to go outside, I climbed a tree and dreamt there instead.