Many users like to file their mail into folders, if only to keep the Inbox empty. While using too many folders isn’t a good idea because it makes managing Outlook items more difficult (especially contacts), filing mail into a few folders can be useful.
You can create as many folders as you need at either the Inbox level or as a subfolder to any other folder. The default folder type is the same type as the parent folder or parent module. You can create subfolders of any type under any folder. For example, you can create contacts and calendar folders under the Inbox.
Is there a limit to the number of folders you can create in Outlook 2013? ...