As mentioned on a past Post (LINK) as the size of the Outlook data file grows Outlook will begin to slow down. Here are tips using the Advanced Find feature to quickly free up the most space from Outlook:
May 2011 archive
Is Outlook just not running as fast as it used to?
Have you noticed Outlook is running slower? Check the size of your PST file. The PST file is a file used by Outlook to store all the data in outlook (mail messages, Contacts, Calendar entries and Tasks). When this file starts to get very large Outlook will begin to slow down.
Organizing Outlook With Folders
Is your Outlook Inbox getting out of control? For most people a vast majority of email needs to be stored and ready to be referenced. If your inbox is getting out of control create a system for filing messages: