Exactly. This advice might apply more to a creative process, where original thought counts above all else. I imagine being truly creative is an exhausting activity, knowing several professional artists (oil paint). You're basically holding a large set of options simultaneously in your head and try to make unique connections between them. The value is not in how many iterations of connections you go through, but coming up with something unique at all.
Development strikes me more similar to solving cross-word puzzles, or playing mine-sweeper, where activity is more guided, focused along a smaller set of options, with lots of trial and error in the process: it's sort of "focused play"/ experimentation. Here it seems more valuable IMHO to keep on going once you're in the flow. You're not looking for that one special connection, that will make your day, but are solving many little problems that aggregate over time.
I could imagine science-based development work to be creatively exhausting as well, where you're trying to prove some theorem etc. Hemingway's advice might apply itself nicely in this case.
I'd like to see more blog posts on how to solve different types of problems. E.g. I know that walking away from a hard problem after you're exhausted works out well (the subconscious keeps on working on it), or as Hemingway proposes, walking away right before you become exhausted.
