Beginning the end of September, 2004, your Inbox will be cleaned of any items over 30 days old, the Sent mail over 30, and deleted items over 5 days.  If you wish to save any messages you will need to create folders to file them in - directions follow:


Directions on how to manage your mailbox size with Mailbox Cleanup

Manage the size of your mailbox to improve the overall performance of Microsoft Outlook:

  1. On the Tools menu, click Mailbox Cleanup.
  2. Do any of the following:
    • View the total size of your mailbox and of individual folders within it.
    • Find items that are larger than a certain KB size.
    • Find items older than a certain date.
    • Archive items using AutoArchive.
    • View the size of your Deleted Items folder.
    • Empty your Deleted Items folder.

Create a folder for messages

  1. On the File menu, point to New, and then click Folder.
  2. In the Name box, enter a name for the folder.
  3. In the Folder contains box, click the type of folder you want to create.
  4. In the Select where to place the folder list, click Mailbox [your name].

Move a message into a folder:

  1. View the folders available:  Click on View, select Folder List.
  2. Click, hold, and drag your email message into your new folder.

About backing up or deleting items using AutoArchive

Your Microsoft Outlook mailbox grows as you create and receive items. To keep your mailbox manageable, you need another place to store — archive — the old items that are important but not frequently used. You also need a way to automatically move those old items to the archive location and to discard items whose content has expired and is no longer valid. AutoArchive takes care of these processes for you.

AutoArchive is on by default and runs automatically at scheduled intervals, clearing out old and expired items from folders. Old items are those that reach the archiving age you specify, and may include such things as the original e-mail you received with the goals for a project you're assigned to. Expired items are mail and meeting items whose content is no longer valid after a certain date, such as a meeting you had four months ago that still appears on your calendar. Although an expiration date is optional, you can define it at the time you create the item or at a later date. When the item expires, it's unavailable and has a strike-out mark through it.

What AutoArchive does with items
AutoArchive can do one or both of the following for items in a folder: Permanently delete expired items; delete or archive old items to an archive file. The archive file is a special type of data file. The first time AutoArchive runs, Outlook creates the archive file automatically in one of the following locations depending on the operating system you're using:
Always Browse and change the location to your folder on the S (Z) drive.
After Outlook archives items for the first time, you can access items in the file directly from Archive Folders in your Outlook Folder List. If you want, you can have separate archive files for individual folders.
When you open Archive Folders, you'll see that Outlook maintains your existing folder structure. If there is a parent folder above the folder you chose to archive, the parent folder is created in the archive file, but items within the parent folder are not archived. In this way, an identical folder structure exists between the archive file and your mailbox. Folders are left in place after being archived, even if they are empty. You work with the items the same way you work with items in your main mailbox. If you decide you want archived items moved back into your main mailbox, you can import all the items from the archive file into their original folders or into other folders you specify, or you can manually move or copy individual items.
Changing how AutoArchive works
There are two sets of AutoArchive settings: global settings and per-folder settings. The global settings — called default settings — determine whether AutoArchive runs at all and what it does by default with the items in any Outlook folder (except Contacts, which is not affected by AutoArchive). The per-folder settings override the default settings so you can AutoArchive individual folders differently. If you don't specify AutoArchive settings for a specific folder, the folder automatically uses the default settings. Default settings and per-folder settings apply to the current mailbox only. If you want, you can also manually archive items.
Company retention policies
In addition to the AutoArchive settings, items in your mailbox may also be subject to retention policies that your company enforces. Retention policies encourage users to retain documents and items for only a fixed period of time as defined by company policy. These policies take precedence over AutoArchive settings.

Automatically delete, move, or color-code all junk e-mail messages
1. On the toolbar, click Organize.
2. Click Junk E-mail.
3. Select the options you want, and click Turn on for each set of options you choose.

Empty the Deleted Items Folder
Do one of the following:
Automatically empty the Deleted Items folder.
1. On the Tools menu, click Options, and then click the Other tab.
2. Select the Empty the Deleted Items folder upon exiting check box.
3. If you want, turn off notification before automatically emptying the Deleted Items folder.
How?
1. Click the Tools menu, click Options, and then click the Other tab.
2. Click Advanced Options.
3. Clear the Warn before permanently deleting items check box.
Note To turn off automatic emptying of the Deleted Items folder, clear the Empty the Deleted Items folder upon exiting check box.
Manually empty the Deleted Items folder.
In the Folder List, right-click the Deleted Items folder, and then click Empty Deleted Items Folder on the shortcut menu.


Most of the information above has been copied and pasted from the help section of Microsoft Outlook.