It does the job for those moments that you needs a refresher

My students are educated in a school where they are treated like adults, and they are taught adult practices. They do their core classes online (Math, Literature, Science, History), and teach themselves using wrtten lessons and informational videos that are provided by the teachers. They can finish their classes any time before the end of the semester, or if they so desire, procrastinate and leave themselves with a heavy work load in the end of the semester. Each student comes to school every day but Friday, to attend two in person electives of their choosing (Friday is reserved for online classwork). Most students will do some of their computer work at the school, in case they have any questions for their teachers. The online courses for math are mostly Khan academy, and every kid loves it. They moved from their normal public schools, came to my school, and loved every part of it. The school is growing rapidly, and has a very long waitlist to get in, and the idea is being replicated all over Colorado. Khan academy according to my students is extremely comprehensible, fun, interesting, and they don't dread doing their math work. According to the vast majority of students, regular traditional math teachers were a large part of why they switched to the school they attend now. I have the freedom and the time because of how I am using khan academy to have an optional math class, during the regular school day, reserved just for students who have questions, who are behind, or struggling with the material. They are given way more individualized learning through this tool than they have ever gotten before. Khan academy is perfect for schools who are flexible, for teachers who are flexible, who care about what the students want.

Khan Academy is great but should not be used often as it is important for students to learn directly from their teachers. The site also does not go into detail of concepts in several classes and should not be used as a substitute for skipping class.

I have a pretty positive opinion of khan academy since I used it to help me learn some material from courses I'm struggling with. The most useful thing is that there are also quizzes that khan academy provides which helps the user really know how they are doing.