I don't think that every programmer should know it off by heart. I do think it should be a reasonably common skill to make common tradeoffs without too much in

I don't think that every programmer should know it off by heart. I do think it should be a reasonably common skill to make common tradeoffs without too much investigation. Besides, the title is an homage to the Latency Numbers article which follows a similar concept. You don't need to memorise numbers, but you probably should be able to reason about them in very vague terms.