Once you get a sense for LLM workflow, sometimes the task is not appropriate for it and you do write by hand. In fact, most code I write is by hand.

But if I want a new system and the specs are clear, it can be built up in stages that are testable, and there are bits that would take some research but are well documented… then it can be a win.

The studies that say devs are slower with LLMs is fair because on average, devs don’t know how to optimize for them. Some do though.

The massive productivity gains I’ve seen come from multidisciplinary approaches, where you’d be applying science and engineering from fields like chemistry, physics, thermodynamics, fluids, etc, to speedy compiled languages. The output is immediately verifiable with a bit of trial and error and visualization and you’re saved literally months of up front text book and white paper research to start prototyping anything

Even if that's true today ( it's not ), it becomes less true over time as tools and models improve.

If you have someone who knows what they're doing with the latest and greatest coding agents it's just not comparable. You can have a Dev open up four or more terminals with multiple prompts running at the same time. A manual person just can't keep up.