I'm looking for a freeware Windows application that will incrementally back up a folder that contains software projects I'm currently working on. My idea of a good app would be one that creates a backup every minute or so while I'm logged in, but only if the files have changed since the last backup. It would hold on to the the last hundred or so versions of each file, along with versions from the last few days. I've tried Easus Free and it's pretty good but it backs up the files even if they haven't changed. I'd consider just programming something simple in Python but I really don't want to recreate the wheel if I don't need to. Any suggestions? Thanks!
Can I suggest that it would be a very good idea to change the way that you are working to use a decent distributed Version Control Software such as git, mercurial or such.
Rather than having automatic incremental backup every 60 seconds or so commit to your local checkout every time that you have a significant set of changes, i.e. it is something that you would like to get back to, with a 1 line description of where you are, and then push to a shadow repository. Many IDEs and Code Editors include interfaces to various version control systems that would allow you to do this with minimal disruption.
This started as comment, but grew too large.
Firstly, great answer, Steve (uvote). And @jason, you were correct to accept it. This answer is not intended to contradict it, just to offer some alternatives for future readers.
Version control is what the software pros use. If you find the command line too intimidating, just search for "githib GUI", e.g https://desktop.github.com/ (there are others).
Sounds like you made you decision, Jason (and, it is a good one).
For anyone who wants a slick GUI, I love PlasticSCM.
It also has an excellent tool for showing the difference between versions, and merging changes.
I've been using this free software for a decade now and it's excellent. Programmed by an individual in a "simple, basic" way, it requires minimal system resources and is extremely flexible, allowing scheduled backups of any group of subdirectories to any target subdirectories you want.
I eventually bought the professional version, just as a donation to the programmer, and the cost was minimal.