It is very easy to neglect clearing out the SENT Folder and this can continually grow if you do not check it periodically and clear it out.
A useful help is to SORT your mail within the folder.
Sorting.
If the email in your Inbox aren't listed by Date Received, then sort it on that column (usually by clicking on Received in the Header column), so that the most recent email is shown at the bottom of the list. Clicking on the column title again will usually reverse the sort so that the most recent items will be shown at the top. You can also sort the email by sender, to collect all of the email from each person together. However, you should always sort it back by Date Received, or you won't be able to find any new mail that arrives, because it won't necessarily be at the top or bottom of the mailbox where it is easily noticed.
This also applies to Other Folders like Sent Box
Once you have the mail sorted to can select a large chunk for deleting. If you are sure you want to permanently delete then hold the CTRL key when clicking on the delete icon.
Tips:
I also have an ARCHIVE FOLDER and I move any mail into that folder that I think I might need to refer back to later. This could be purchase reference numbers, passwords, payment details etc
There is a Option setting within Outlook Express that will empty the Deleted Items Folder on shutdown. If you are sure about doing this then set the option.
Tools - Options - Maintenance - Empty Messages from Deleted Items Folder on Exit
