OS X El Capitan (10.11.6)
Over the years I've installed programs and software on an as-needed basis, often as a quick fix to get things to work when I need them. This works well in the moment, but not long-term. I have who-knows-how many versions of Python and TeX on my computer and there are undoubtedly other remnants of old software and drivers hiding somewhere in plain sight.
I would also like to free up my cluttered drive.
I don't claim to be an expert on my filesystem, nor do I understand really what is installed where. I want to avoid doing a clean install of the OS and then having to reinstall all of the programs/dependencies I need as well as move all of the files I want from my backup.
What directories can I (selectively) nuke to purge my computer of most of its installed software and files related to them? What should I be careful not to delete? Is this endeavor even worthwhile; should I instead just reinstall completely and go from there?
As another potential course of action, what software would you recommend to purge my computer of the software/aux files I've collected? Note that I am mostly interested in removing software and related files that I would expect software cleaners to consider "not junk," e.g. an installation of Python I no longer use.
Thanks in advance.