No developer is a solo developer. At a bare minimum, Present You is working with Future You. And Future You would appreciate it if Present You documented your work.
And no, talking to the rubber ducky doesn't help.
Anything you talk to the rubber ducky about probably deserves writing down.
In the beginning of my career I was much more diligent about this (but I also didn't write as readable code, so it was more necessary); the exercise was simple:
When I hit the stupid part of the day (the end of the day), I go back over code. When I don't understand something, I write down something about my confusion. In the morning, when I'm back to being smart, I convert all the confusion to comments and/or better code.