I have created an Add-In using Python. However, when I edit the Python script for that Add-In and re-create the '.esriaddin' file, I don't get updated results when using that Add-In. Do I need to re-create the Add-In each time when I edit my Python script to cater to changes?
The steps for editing existing Python add-ins are described here.
One of those steps is to Test your add-in and the first step of that is to "Make the add-in file" by running the makeaddin.py script.
Consequently, I would expect that you do need to re-create the Add-in.
It is certainly worth giving that a try.