Automator is a really clever tool included in every Mac, which lets you automate common tasks you perform with an intuitive user interface and no need to have any knowledge in programming.
Rotate Files is an Automator plugin, known as an Automator Action, particularly designed to work with the Rename Finder Items Action.
This action has an option named Make Sequential which is used to adds a sequence number to the files it receives, but it does not impose any upper limit to the number of files in the sequence; this possibility may be useful in various situations, for example when creating a workflow for generating backup files, but with an upper limit to the number of backups you want to preserve.
How it works
Here enters Rotate Files: with this action you can set the maximum number of files belonging to a certain sequence, older ones will be just moved to the trash.
Moreover you can set the sequence start value and also the sequence step value if needed and you can force removed files to be immediately deleted instead of being placed in the trash.
Finally you can also force the sequence number to have a specific number of digits, different from the one currently used.
I have prepared a few sample workflows, which show the most common uses for Rotate Files, that you can use as a starting point for your own needs.Download at Cnet.com