You don't have to do anything, but if you'd rather customize your archiving, Outlook makes it easy to take control. You can archive different folders at different rates — or not at all. You can set up archiving rules on a folder-by-folder basis. You can also exclude entire folders from the process. It's your choice.
You start by right-clicking the folder, clicking Properties, and specifying your custom settings. (We've shown this in the picture.)
For example, maybe you're working on a special project. Messages for that project are stored in a folder called Contoso. At archive time, messages that you save there should be archived when they are two months old (rather than at the standard six-month setting). And maybe you have a different folder, for personal correspondence, named Family, in which messages should be archived once those messages reach a maturity date of one year.
Once you choose these settings, AutoArchive will just happen. That's what makes it so easy. Still, do remember to do periodic tune-ups. As you add folders, you'll want to adjust their AutoArchive settings.