With the Cloud Storage plan, you can watch any video recorded in the past 3 days when you sign up for a 3-day plan, and the past 7 days when you sign up for a 7-day plan, and so on.
For example, if you buy a 7 day monthly storage plan on April 1st, it will expire on May 1st and stop any recording. And you can only view the most recent 7 days video