Those that say “keep your user documentation up to date, not only for others but for yourself in the future,” are absolutely correct. You will forget, and you will need to go through your old code to remember how your tool works. Might as well update the docs while you’re at it.
Yeah, it happens. Today it was using something I wrote to make sequence diagrams. I couldn’t remember how I could specify the name of the SVG file so into the code I had to go. At least it’s written down now.