Is that so? So a kid will always prefer to use a tablet than visit their fun friends or do something exciting? They likely use it because they are bored, just like adults are. We're all humans in the end.

Just let them use it, but if they use too much, you need to give a good example of what would be an alternative, also what are their responsibilities. If they are getting good grades and keep their room organized, why can't they do whatever they like? This smells like abuse.

Is it really different if a kid is exposed to cigars at 12 or 18? I don't think so. I just wouldn't give them cigars and would make sure that they know how bad this is for their health, as well live in a community that would lessen the likelihood of such thing happening. You don't have control of whether this will happen though.

But in the end, they'll fulfil their own destiny, if their ultimate destiny is to smoke cigarettes or do heroine when they grow up, let it be.

Try to conquer them with your example, and they will want to follow your footsteps. But if you are boring adult with a shitty life and sad, be sure they'll find another example to aspire to.