For those of you with children still at school, do you limit how much time they spend on social media? If so, how?

They can spend as much time as they like after they’ve finished their homework, piano practice, chores etc.

Android phones have limit control, 1.5 hours and you can see what apps they use. Personally, I don't mind if they're talking to friends on LINE, anything else, I'd warn them of the consequences to their mental health, suggest them not to use such app for too long.