With AutoArchive, moving messages just happens (after you get the prompt if you've selected that check box). However, you do get to control a few things. AutoArchive has a number of default settings. And they're yours to change. This means that you get to specify what "old" means.
For some people, mail may seem old after two weeks; for others, it may be two months. You're the one who gets to decide — and you can do this on a per-folder basis if you like. (We'll talk more about that later in this course.)
You choose settings for message maturity in the AutoArchive dialog box (we've shown where in the picture). Each time AutoArchive runs, anything meeting the "old" criterion will be sent to the Archive Folders folder. In the example in the picture, anything older than six months will be moved to Archive Folders.