I use Udemy for training myself. I pick the top rated courses when they are on sale at 10$ /course. Even the top rated course are not great. There is always a difference between what is taught on course and what we do at work. And some authors do not update the course, so we are left with somewhat obsolete courses (eg, no update after React hooks is released). And finally, there is a difference in courses available and courses we need. For eg, no decent course on Gatsby or Relay.