If you set your .Mac account to automatically renew each year, you can verify your .Mac renewal settings by accessing the Account section of .Mac. The Account Settings page displays the details of your .Mac account, including your storage information, bandwidth, and the date that your account is scheduled to renew.
If your account is within 60 days of renewal, you will see a button that says "Review my Renewal Settings." Click this link to view or modify your renewal settings and add or subtract upgrades to or from your account, respectively.
If you are not within 60 days, you can enable or disable the Auto-Renew option; just click the Credit Card Info button on the Account page and make your changes on the resulting page.
Note: Any upgrades that you add or remove on the Renewal Settings page will take effect on your renewal date.