Automatic deletion of e-mail based on how old it is

You can use retention policies to automatically delete e-mail based on how old it is. The setting is put on individual folders.

1. Go to webmail (OWA)
2. Navigate to the folder you want to set automatic deletion for. 
3. Right-click the folder and  select Assign policy
   
   
4. You can then select:
   • 1 Year Delete (1 year)
   • 3 Year Delete (3 year)
   • 5 Year Delete (5 year)
   • Never delete (Never)
   • Use parent folder policy

The rule you set here says that Exchange should delete all email older than 1, 3 or 5 years. Do you have e.g. a folder containing e-mail that is particularly important, you can choose that Exchange should never delete e-mail in that particular folder. If you have a folder for invitations to events like christmas and summer parties and the like, you can set til to automatic deletion for emails older than 1 year.

Use parent folder policy sets the deletion rule from the folder containing the one you have selected. 

Note: The retention policies do not immediately delete messages permanently. You can use Recover Deleted Items for 30 days after the message was "deleted".