PIP has a habit of re-downloading same packages every time you hit pip install package_name. That's not so cool, especially, when you deploy packages from requirements.txt and one of the packages failed to build, restarting pip install -r requirements.txt would lead pip to redownload all the packages again.
Thankfully there's a way to fix this easily, create a configuration file named ~/.pip/pip.conf, and add the following contents:
