Have kids. They are great mirrors of what we do. How did I know when my device became a negative? When I watched my kids on their devices and act like me, oblivious to the world and short with people who intrude. We have set rules about when devices can be used and where. No bathroom. No kitchen table. If we go somewhere, they devices get put in my bag when we get there(car travel is okay). Homework(or chores) get done FIRST before devices get turned on. And once it is plugged in for the night(at bedtime), it is off limits until the next day. No, you can't just check FB one more time! No, emails can wait until morning.
Often when we go out to eat, we are literally the only family talking to each other while we wait for food to come. Every other table is full of people on mobile devices! Sad, me thinks. Or at a stop light, I look over and one guy next to me is on his phone talking and on the other side of me, a teen driver is texting.
I think we as a society need to learn rules for our new world. Easy access is too easy to use at not smart times.