By Diane Poremsky
Outlook's Rules Wizard has a neat but often overlooked option to act on messages after they're sent. These rules run as the message leaves your Outbox and provide a variety of options.
Do you have a small mailbox and don't want to save large messages? Create a rule that copies all messages to a different folder and create an exception for "except with a size in a specific range", then disable saving copies of messages in the Sent Items folder in Tools->Options->Preferences->Email Options.
Do you want to save sent messages to different folders based on the recipient, the account, or the subject? Create a different rule for each folder. Note that if you use a "when they arrive rule" to filter messages to folders, Outlook has the ability to save replies in the folder with the original, except when the message is in the Inbox. You can enable this option by navigating to Tools->Options->Preferences->Email Options->Advanced Email options.
Maybe you want to store your sent messages in the Inbox and use a threaded view? Merely select the Inbox as the specified folder.
Because the After Sending rules copy, not move, the messages, you should disable saving copies of sent items (Tools->Options->Preferences->Email Options and remove the checkmark from Save copies of messages in Sent Items folder). If you decide to continue saving sent items, you'll want to delete the contents of the Sent folder on a regular basis. Open the Sent Items folder and select all messages (Ctrl+A) then press Del or set up AutoArchive to delete the older sent messages every few days.
You can delete messages based on specific criteria, but you'll need to create a "when they arrive" rule and use the Rules Wizard "Run Now" option to run a rule (or rules) on the Sent Items folder to delete the messages meeting your criteria.