The folder monitor lets you specify certain folders you want to have monitored for files of certain ages. For example, you may want to remove all files that are older than 60 days in a certain location and move them to another archive location, etc. Or maybe you want to remove empty folders after they are 20 days old. This is where you would do this.

You can specify a custom CrushTask plugin to run as well allowing you to move items off to another SFTP server, or generate emails, etc. You have unlimited things you can do at that point.