HDCleanUp is an easy-to-use disk cleaning utility. HDCleanUp does NOT delete or act on any files until you decide when it's appropriate. All task related files first show up in a list, allowing you to decide which files to delete or act upon. If a file is deleted (moved to the Trash), it is recorded in the Trash Log window. Change your mind about moving a file to the Trash? If you haven't yet emptied the Trash, the Trash Log allows you to move the file back to its original location.
HDCleanUp Tasks:
Application Uninstall.  Simply drop an application onto the window, and HDCleanUp shows you a best-guess of all the application’s related files.  Move them all (except the application) to the Trash with a click of the mouse.

Duplicate Applications. You download an application. Months later you download an updated release, however, you forget to delete the older release.