Spaced repetition is a learning technique where you review information at increasing intervals over time, timed precisely when your brain is about to forget it.
It's not a new idea — German psychologist Hermann Ebbinghaus described the "forgetting curve" in 1885. But software now makes it practical for everyday learning.
Ebbinghaus's research showed memory decays predictably:
Without review, nearly 80% of what you learn is gone within a month.
Each time you successfully recall information, the forgetting curve resets — but at a slower decay rate. Review it again at the right moment, and the curve gets even shallower.
Optimal review schedule (example):
After 5–6 reviews with this spacing, the information moves into long-term memory.
Modern spaced repetition apps (Anki, SuperMemo) use algorithms to calculate exact review times. The SM-2 algorithm — developed in 1987 — calculates intervals based on:
You don't need to understand the math — the app handles it. Your job is to rate your confidence honestly after each recall attempt.
The real power comes from combining spaced repetition with active recall — not passively re-reading, but actively testing yourself.
The workflow:
Tools like SimpleQuizMaker generate quiz questions from your materials, which you can then use as review material on your spaced schedule.
High value:
Lower value:
Anki is the gold standard free spaced repetition app:
Pro tip: Import question sets from SimpleQuizMaker into Anki for instant study decks.
How long should I study with spaced repetition each day?
20–30 minutes of focused review is more effective than 2-hour cramming sessions.
What if I miss a day?
Don't panic — just resume where you left off. The algorithm adapts. Consistency over perfection.
Can I use spaced repetition for essays or complex topics?
Not directly. Spaced repetition excels at discrete facts. For complex topics, use concept mapping and practice problems alongside.
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