This vastly differs depending on what software you write. I have done lots of necessary performance optimizations. Of course, there is a balance. To say never f

This vastly differs depending on what software you write. I have done lots of necessary performance optimizations. Of course, there is a balance. To say never first optimize, is as bad as optimizing everything, in my opinion. It should require a case by case "study" of whether it is worth it. This kind of judgement comes with experience.