PDF files, the same as other types of files, need sometimes to be renamed, and for this task a good utility is A-PDF Rename. It isn`t your typical renaming program that adds a prefix/suffix, as it uses other criteria to rename.
With A-PDF Rename you can batch process PDF files from the information contained in each of them; metadata, attributes, properties (size, date, creator, subject, keywords etc).
This way you`ll get, with A-PDF Rename, a totally personalized renaming that is in accord with the content of each PDF. For programmers it`s interesting to note that it can be referenced and run scripts to make changes in each of the files to rename.