Keeping the messages you send can be a useful way to track who said what to whom. But, you don't necessarily need to keep this kind of record in your mailbox—which is where a copy of the messages that you send are stored (Sent Items) unless you archive them.
To specify archive settings for AutoArchive, right-click the Sent Items folder, click Properties, and select the AutoArchive tab.
If you prefer to archive manually, click Archive on the File menu, and scroll to select the Sent Items folder.
