Most Excel users are unaware of modern software practices, and wouldn't know where to begin. The software developers don't know how to teach us. Perhaps someone should create a series of practical 15 minute lessons, each of which can be applied to an existing spreadsheet, to make it better.

I have literally improved my Python code in 15 minute chunks, but it's a lot easier to find good coding advice for Python, plus the editors provide things like built-in linters and style checkers that help quite a lot. And Python wasn't my first rodeo, so I already understood the value of good coding practice and some of the theory behind it.