Also, these old versions are useless as a back-up because they are stored on your main disk and are automatically deleted when you delete the corresponding file. Even if you do need an old version of a file, you can restore old versions if you have enabled the 'TimeMachine' backup-feature of OS X. For most files you know that the latest version is 'good' and that you won't ever need access to previous versions anymore.
These previous versions can add up to many gigabytes of 'wasted' disk-space since it is common to have many hundred old versions for the files you have been working on. Since OS X 10.7 'Lion', most Mac apps automatically store not only the latest version of any document, but all previous intermediate versions are stored too.
VersionsManager is an application that allows you to inspect and optionally delete old 'versions' of your documents that have been stored automatically by your Mac.
