Spaced Repetition. How to remember what you learn.

Review a fact after 1 day, then 3 days, then 7, then 21. Each review resets the curve of forgetting. You study less per session but remember more over a year. Cramming puts information into short-term memory. Spacing puts it into long-term memory. They look the same for a week. After a month, the difference is large.

• Hermann Ebbinghaus discovered the forgetting curve in 1885. Without review, you forget about 70% within 24 hours.
• Free apps like Anki use spaced repetition automatically. You add the content. The app schedules the reviews.