
I think “harming themselves” is a good metric and kind of covers all the bad things that results from the others. But I do think there’s an argument to intervene before any harm happens. If your kid is doing weed etc they aren’t necessarily harming themselves, but I would want to intervene to make sure they know the importance of moderation, safety, and possible consequences so that they are watching themselves *before* they are harmed
I am totally fine with my child 16+ experimenting with drugs/alc, monitored at home but if it becomes an issue where they are using without me or without telling me then I will intervene, I know kids that age will do it anyway so Id rather it be done safely and to my knowledge than otherwise, for any harm self inflicted or otherwise im 100% stepping in