Google has introduced a new billing system for the AdWords account holders. It's the ‘Retry card’ button.
Once you've resolved a decline issue with the credit card you're using for your AdWords account, this convenient button allows you to retry charging your existing primary or backup credit card without having to re-enter your credit card information.
If your credit card has been declined but is ready to be retried, just go to the Billing Preferences page of your 'My Account' tab and click 'Retry card' to get your ads back up and running in one easy step.
Now that is what we call convenience.