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I suggest the budgeting approach: Parents pay for a certain amount of data each month, the children track how much they’ve used, and then they pay for anything beyond that allotted amount.
It’s simple enough in theory. Carriers lets customers check to see how much data each person in a family plan has used so far during the month, and the privilege of having a phone should come with the responsibility of keeping track.
That approach does, however, require you to sit down with your teenager and identify the sources of data drain and perhaps set rules for when those apps ought to go off. The Times’s Wired Well columnist, Jennifer Jolly, lives with a data-draining teenager. She suggests turning off any features on a teen’s phone that drain data automatically in the background. Also, track the apps that use the most data and limit data hogs like Spotify or Snapchat to times when the teenager has Wi-Fi access. One additional hint: The more video an app records, transmits and receives, the higher the data bill is likely to be. Call your carrier or consult online forums if you need more help.
In an ideal world, this approach teaches patience, self-control and restraint. Your kids can always watch a video a little later over Wi-Fi, after all. And many messages – most, even – can wait a bit.