Most kids here get phones around 9/10 when they start walking to and from school alone, so before they really start using social media so it isn't a sudden one day they are using it, next day they aren't thing. Also children are changing for other reasons hitting puberty, generally growing older etc, and there is other stuff going on in their lives - cause and effect can be hard to pinpoint. There are also grey areas - is messaging your friends social media? Watching videos on YouTube?