DD is 12. No TV, but screen time on her tablet, probably 1-2 hours per day during the week. That includes music, which she loves, and while there is a visual element it is little different to listening to music on the radio.
The rules are school, after-school activities (she has a dance class every day, sometimes 2), and homework have priority. Screens go off at 8pm (an hour before bedtime), for a shower/bath, snack if she wants it, brush teeth, have a cuddle and chat with me etc. She can read in bed, or listen to the radio or audiobooks, but no screens. She reads for pleasure, fiction and non fiction.
Weekends have more screen time, but again, it fits around the more important activities. And also I encourage watching programmes that involve a degree of sustained focus, so if she is watching endless mindless snippets on youtube I am more likely to make her switch off than if she was listening to music or watching something that had some sort of challenge to attention and thought.
As a previous poster has said, it is not screen time as such, as screen time can cover a range of positive options. It is screen time pushing out other activities, especially physical activity.
I think our children need to learn to handle technology as it develops, rather than shut it out altogether. To understand the potential drawbacks and the potential positives, and fit it into their lives in a constructive way, as part of a range of leisure and educational activities.