Great for backing up each version of a worked on file. The copy changed files tool is a free program that lets you copy changed files from one directory tree to another. The program only copies changed files, leaving all other files behind. Needed if you have a vast amount of images/documents/source code files that you only want to make a incremental backup of, You have a lot of customer websites that you maintain and only want to update the changed files, You need to copy changed files only from one directory tree to another, or You take a lot of pictures you want to backup several times a day to a DVD or another media where you cannot overwrite only append to.