Spaced Repetition

Spaced Repetition is the most powerful study technique for long-term retention, backed by over a century of cognitive science. Hermann Ebbinghaus discovered the forgetting curve in 1885 — memory decays exponentially unless you review at increasing intervals. Spaced repetition systems (SRS) like Anki exploit this by showing you flashcards right before you'd forget them. Research shows spaced repetition produces 200% better long-term retention than massed practice, outperforming #2 Active Recall in sustained recall over months. Medical students swear by it for memorizing thousands of drug interactions, and the optimal intervals — 1 day, 3 days, 7 days, 21 days, then monthly — are supported by decades of data. This technique is 50% more efficient than cramming for exam scores after 30 days.