I have to say that it boggles my mind on a regular basis when I start talking to end users during a session or when interviewing users in client engagements to find out that they don’t quite understand how the end user and site collection administrator recycle bins work. Most of the time I find that users have the perception that it’s a serial process where once they delete a file, they have thirty days until the file is then moved to a secondary recycle bin where a new timer kicks off – unfortunately this is wrong.
“By default, items in the Recycle Bin are deleted automatically after 30 days. Regardless of whether or not an item is sent to the users’ Recycle Bin or to the Site Collection Recycle Bin, items are deleted automatically after the number of days that the server administrator specified in Central Administration.”
As you can see, it’s plain and simple, 30 days is 30 days, no less no more.