He isn't saying that you should spend time on optimising your code, rather that you should write performant code from the beginning by not giving the cpu more w

He isn't saying that you should spend time on optimising your code, rather that you should write performant code from the beginning by not giving the cpu more work than it needs to do to perform the task, typically by avoiding OO paradigms, followings things like SOLID, etc. Then if needed, real optimisation can handle the hotspots in your code and is typically something that only a few of an orgs best engineers can do properly, but if everything is slow then its an insurmountable task for these few engineers. If you want to understand what he means with this watch the refterm series. https://www.youtube.com/watch?v=pgoetgxecw8 https://www.youtube.com/watch?v=pgoetgxecw8