David wants to know:
How far back in history will an Outlook\Exchange calendar go?
It goes back as far as you want it to go. If AutoArchive is enabled, you can configure it to either delete or archive old calendar items as they age. If you are on an Exchange server, the administrator may have the server configured to delete old items using Exchange server's Mailbox Manager.
To check your AutoArchive settings in Outlook 2010 or Outlook 2013, go to File, Options, Advanced, click on AutoArchive Settings. If you are using Outlook 2007 or older, go to Tools, Options, Other and click on AutoArchive Settings.
In all versions: To configure any folder to use different AutoArchive Settings, right click on the folder and choose Properties, AutoArchive.
More Information
Read more about AutoArchiving at Slipstick.com:
Using Outlook's AutoArchive Feature
How to locate, read, or recover items archived using AutoArchive
AutoArchiving by Received Date in Outlook
Published May 8, 2006. Last updated on April 6, 2014.