Backups can be really useful, because if you format the HD or maybe if it crashes, you will have all your data ready to be recovered which can be a good surprise in those annoying situations.
Identities, email messages, email account settings, message rules,
the address book, list of blocked senders, signatures and settings as well as
backup and restore your Favorites, Windows Address Book and My Documents, all those stuff will be safe and ready to be restored.
Furthermore, you will be able to create several copies and decide what you will backup. If you use Outlook Express this is a must have, you?ll save a lot of time and annoying moments.