[hprotagonist]

It's a free-for-all. (welcome to my world :( )

Something small but meaningful that I believe in are tools like versoneer (https://github.com/warner/python-versioneer/) which bump the version of your code on every commit.

Then, embed this version string in all output. Figures, serialized data, whatever.

It is very powerful to be able to point at a figure and say "this graph was produced by precisely this code". If you're feeling particularly anal, include the hashes of the datasets that generated it too.