You can create additional folders and organize your messages amongst the folders.
Most users use just one mail file and simply organize their messages using folders.
This will help improve PMDF MAIL's performance which decreases with increasing file size. You can create additional mail files and move messages to them. This is useful, for instance, for archiving old messages. Within that mail file, you could organize the messages amongst the twelve folders JAN, FEB, MAR, APR, etc. A folder is created the first time you move a message into it.