I feel like spending time learning "domain specific knowledge" is much more effective than "general rationality techniques".

However, reading Lesswrong is what prodded me towards getting better at spending my time effectively, really getting into a growth mindset. My only problem nowadays is that there are too many things I want to learn, and that's a much better problem to have; I know I can, I just have to pick and choose. I'm getting better at that, too.

Maybe the same would have happened anyway, but I don't think it would have happened quite as fast.