I think many of the qualities mentioned have nothing to do with “clean” code (like performance). My metric for cleanliness has become simpler over the years: M

I think many of the qualities mentioned have nothing to do with “clean” code (like performance). My metric for cleanliness has become simpler over the years: Mean Time To Comprehension. The less time it takes for someone else (or future me) to understand how and why my code does what it does, the cleaner that code is. This is surprisingly accurate and actually useful.