ANKI is a great tool. It schedules questions based upon how well you answered the question the last time. As I do courses in Khan Academy, I find my self making Anki cards to ensure that I retain what I learn long-term. Since KA already knows what questions I've answered, including ones I had to do over, I wish there was an option to either generate ANKI cards based on quiz questions I've taken, OR have ANKI like functionality as an option I could turn on in KA. There is considerable research that shows that the ANKI method is optimal for long term retention of knowledge.