His example makes perfect sense... when the "naive" implementation duplicates stuff over 100 or 200 LOC. I've had joyful experience of working with duplicate c

His example makes perfect sense... when the "naive" implementation duplicates stuff over 100 or 200 LOC. I've had joyful experience of working with duplicate code that spanned over multiple thousands of lines. I still fondly remember a PHP script generating multiple xml files, supporting different versions of format. (It was an e-commerce format for exporting and exchanging products data). And with multiple inconsistencies among this copy-pasta that have accumulated over time. The problem here is the boiling frog syndrome. Duplication rarely starts with thousands of lines. It grows over time, and the longer you put up with it, the harder it becomes to roll it back. But as long as it grows slowly, the frog feels comfortable. Clean code approach may get overzealous, the potential for fanaticism may even be sort of inherent to this approach (I agree), but it stems for acknowledging this simple, sad truth. The truth is that complexity of naive code is kind of like cancer. If you don't detect it before it actually begins to hurt, it's not great news.