The first month for all devices will be billed in advance from the credit card submitted at the time of subscription. The subscription term will not start until the device actually is shipped, and after that, billing will occur monthly from the start of your subscription.
Monthly billing will occur on the same day each calendar month. (If your subscription starts on either 29th, 30th, or 31st, you will be always billed on the last day of that month.)
After your contract term is finished, it is automatically changed to a month-to-month contract at the same convenient rate, until you're ready to return the device!