You should delete a file or folder when you no longer need it, when your disk is getting full, or if you created the file or folder by mistake. Before you delete anything, however, it is a good idea to make a backup copy in case you discover a need for it later; make that backup copy to a floppy disk if you're trying to save disk space. See Lesson 18 for directions on how to copy files and folders.
In Windows NT, deleted items are moved to an area called the Recycle Bin and remain there until you empty the bin. Deleting items to the Recycle Bin does not provide any extra disk space. Those items remain on the disk until you empty the Recycle Bin.