Child up to age 13 - internet access via PC tower in a public space. No phones, no tablets. I log into router settings to restrict internet access to their machine, (mac address,) when they should be sleeping. I use router to block websites, no FB or instagram. Hell, I will change the wifi password and make them prove they have done their homework/chores to unlock the password for the evening. Ages 14-16 - give them their own pc/tablet. Router still restricts website access, but I stop restricting the times they can access internet. Age 16 - get them their own phone. Presumably I have been talking to them about responsible use of the internet all along, but I reiterate all of the key lecture points. Use router and parental controls to monitor what they are looking at without restricting it. Discuss anything problematic. This is a stage in a young person's life where they should be learning to take personable responsibility for their fuckups within reason, so I am more willing to let them experiment and make mistakes within reason. 18+ - no restrictions. Consider transitioning them to their own cell service that they pay for on their own, so long as it's something they can reasonably afford with their own wages, assuming they have their own wages.