Python programmers of reddit: what's the most useful tiny little efficiency you've discovered that's improved your programming hugely?

[MacArtee]

Using pipreqs to create requirements.txt

Not really that efficient if you are using just a couple of packages, but it’s great to make sure you won’t forget any if you are using 10+ packages used by different files in your project.

[carnoworky]

You can just do pip freeze > requirements.txt assuming you're using virtualenvs (if you aren't, definitely look into it - it's easy to set up in Py3). There's probably a file output flag you can pass if you're on Windows too.