Duration : 00:21:18
In this video, the speaker identifies six common mistakes that developers make when using the useState and useEffect hooks in React. The first mistake is using state unnecessarily, such as when the value is only needed on form submission, in which case a ref could be used instead to avoid unnecessary re-renders. The second mistake is not using the function version of the useState setter, which can lead to unexpected results when updating state based on previous state values. The speaker recommends using the function version to avoid this issue.