I think they make good devs 2x more productive for the first month, which then slowly declines as that good dev spends less time actually writing and understanding and debugging code until it falls well below the 1x mark. It’s basically a high interest loan people take against their own skills. For some people that loan might be worth it. Maybe they’re trying to change their role in an organization and need the boost to start taking up new responsibilities they want to own. I think it’s temporary though. The slow shift into “skim mode”, where the authors just don’t quite put that same amount of effort into understanding what’s being churned out. I dunno, that’s just what I’ve seen.

I think on average a dev can be x percent more productive, but there is a best case and worst case scenario. Sometimes it's a shortcut to crank out a solution quickly, other times the LLM can spin you in circles and you lose the whole day in a loop where the LLM is fixing its own mistakes, and it would've been easier to just spend some time working it out yourself.

Good devs are still learning how to use LLMs, and so are willing to accept the 0.65x once in a while. Any complex tool will have a learning curve. Most tools improve over time. As such good devs either have found how to use LLMs to make them more productive (probably not 10x, but even 1.1x is something), or they try them again every few months to see if things are better.

I just spent a day trying to get Claude to write reasonable unit tests and then after sleeping on it, reverted everything and did it myself. I’m not gonna be using it for a while because it 0.5x’d me once again

Yep, that's why very accomplished, widely regarded developers like Mitchell Hashimoto and Antirez use them. They need to make programming more challenging to keep it fun.