This is basically my career. I had a stable gig for my first handful+ of years after college and never much encountered the leetcode grind people talk about unt

This is basically my career. I had a stable gig for my first handful+ of years after college and never much encountered the leetcode grind people talk about until recently. A lot of the O(X) stuff is self apparent when you're writing practical code: lotsa slow loops within loops == bad and should be avoided where possible. When I started doing job interviews it was a little bewildering how much some companies focused on this. I ended up taking a job whose interviews focused on more practical skills and also stressed a good culture fit and understanding of development practices. It feels like a place I'll be happier. I think you're right about the JIT aspect to this sort of thing--that's really what being an engineer is about in my experience. When you encounter a problem, figure out how to do it better. If my filter/sort/whatever is too slow for a specific application, I'll do some research and implement something more appropriate.