Spaced Repetition: How to Remember Everything You Study

Hermann Ebbinghaus discovered the "forgetting curve" in the 1880s: without review, we forget approximately 70% of new information within 24 hours. But he also discovered the solution: reviewing material at increasing intervals — what we now call spaced repetition — dramatically slows the forgetting curve and builds long-term memory.

How Spaced Repetition Works

Spaced repetition is based on the principle that reviewing information just as you're about to forget it strengthens the memory trace more effectively than reviewing it when it's still fresh. Each successful review extends the interval before the next review is needed.

A typical spaced repetition schedule for a new piece of information might look like: review after 1 day, then 3 days, then 7 days, then 14 days, then 30 days, then 90 days. By this point, the information is typically in long-term memory and requires only occasional review to maintain.

Implementing Spaced Repetition

Anki (Free)

Anki is the gold standard for spaced repetition. It's a flashcard app that automatically schedules reviews based on how well you remember each card. It's free, open-source, and has a massive library of pre-made decks for almost every subject.

The Paper Method

If you prefer physical flashcards, the Leitner Box system provides a simple physical implementation of spaced repetition. Cards are sorted into boxes based on how well you know them, with boxes reviewed at different frequencies.

Spaced Repetition + AI Study Notes

The key to effective spaced repetition is having good flashcard material. AI study notes tools like StudyNotes AI can generate key concepts and definitions from any YouTube lecture — giving you the raw material for your Anki deck in seconds. Instead of spending 30 minutes creating flashcards from your notes, you can generate them automatically and spend that time on actual review.