I’m just cross-posting my reply to another thread, apologies in advance for not reading through everything already said here:
To give a little context to that, I often write scripts for one specific task, e.g. processing some data set. For that, I might need a specific set of packages outside the “usual” ones. At the moment, I usually create a separate conda environment for each, install the “usual” packages, install the specific packages for this one task, note them down in a requirements.txt file, do the work, delete everything. It would improve the workflow somewhat to just be able to pip install --local whatever I don’t usually have in my environment. That could still just be pip install --local -r requirements.txt to keep things simple.