Problem: In my exchange 2010 server, the default deleted item retention was set to 14 days. My organization wants it set to 30. Tried messing with the retention polices but was getting confused on how it worked and how it would apply to. In the end, it was still set to 14 days
Solution: This setting can be modified, along with the default size of the mailbox within the properties of the database.. Go into the Exchange Management Console, click on Organization Configuration and then select Mailbox. Click on Database management and right click on the Exchange DB you want to change and select properties. Select the Limits tab and there you can make your deleted item retention change.