React is a fantastic tool to implement complicated applications fast, we all know it. But are they going to be fast when implemented fast? Let’s talk about re-renders and their danger in react: how easy it is to make a mistake, why some small mistakes can have a huge downstream effect, and how to avoid and prevent them. This is a deep-dive type of talk, that focuses on why React components re-render, what kind of performance impact it can have, and what to do about it.