Comment by boutell

Knowing all of these is exactly what a developer shouldn't need to do. Fix "big O" problems in your own code. And be aware of a few exceptionally weird counterintuitive things if it matters on a "big O" level — like "you think this common operation is O(1) but it's actually O(N^2)". If there actually are any of those. And just get stuff done.

I guess you could find yourself in a situation where a 2X speedup is make or break and you're not a week away from needing 4X, etc. But not very often.