When you purchase Hidden your subscription will be set to renew automatically each year.
If you would like to disable auto-renewal and pay by credit / debit card manually each year, this can be done from your hiddenapp.com account page. https://hiddenapp.com/account/
You will be sent a notification email a few days prior to the expiration of your subscription.
If your subscription comes to an end and you choose not to renew, your account will become inactive and you will no longer be able to track your devices from the Tracking Control Panel.