Have a dd10. We've allowed 2 hours of screens on weekends and 30 mins in the week after school. She is in activity clubs until 6 most days and until 9 at guides on one night. Screens are switch, iPad games and you tube
She can watch tv in addition but no you tube in the week.
We have tried timers but we have arguments about how long she has been on it. We use a timer and write it down now but she still hates coming off and it's just one more thing or I need to finish this for 2 minutes. It's the first thing she asks for when we get in the door after any time out as a family.
Her attitude and behavior is not great after being on a game .. or watching you tube
What works for you?