We've made it easier for you to keep track of your additional lines and devices. Simply opt your additional lines in to My Account Controls and we'll let you know by text message when they're running low on data.
As the account owner, you'll have better control over what happens on your account. You'll be automatically notified when any additional lines are almost out of data, and it'll be your decision if you want to buy more data or Extras.
It's up to you how many lines you opt in, and you can also set caps which can't be removed, unless you choose to.