Statistics and complex variables aren't taught in a way that gives you understanding, they are taught plug and chug. That is why it feels like a breeze and then

Statistics and complex variables aren't taught in a way that gives you understanding, they are taught plug and chug. That is why it feels like a breeze and then everyone forgets everything. Basically nobody gets a good understanding for those subjects from taking courses, so you need memorization techniques for them. Calculus and linear algebra are good examples of courses taught in a way that gives understanding, lots of people understand those after taking the courses, so there you shouldn't use memorization techniques. So the reason you needed spaced repetition for statistics was that you never understood statistics, you just memorized it, like basically everyone else. It isn't wrong to do that btw, statistics is useful even when you just memorize it which is why it is taught that way, but don't trick yourself into thinking that you really understand the material the same way you did calculus or linear algebra.