The forgetting curve
Over a century ago Hermann Ebbinghaus showed that memory decays predictably: learn something once and you forget most of it within days. Each time you review, though, the curve gets flatter — you forget more slowly than before.
Spaced repetition exploits this. Instead of reviewing everything every day (wasteful) or once and never again (useless), you review each item at expanding intervals — a day, then a few days, then a week, then a month — timed to just before you’d forget it.
Why spacing beats cramming
The spacing effect is one of the most robust findings in learning research: the same total study time produces much stronger long-term memory when it’s spread out rather than massed into one session. Cramming feels efficient because the material is fresh, but that fluency fades fast.
Spacing also makes review cheap. Once an item is well learned, its interval grows to months, so each day you only review the handful of things actually about to slip — not the entire deck.
SM-2, FSRS and how schedulers decide
Early apps used the SM-2 algorithm (from SuperMemo): grade a card and it multiplies the interval by an ease factor. It works, but it’s a rough heuristic. Modern schedulers like FSRS (Free Spaced Repetition Scheduler, now built into Anki) model your memory more directly — estimating, for each card, the probability you’ll recall it — and schedule the next review to hit a target retention.
In practice you just grade how it went — typically Again, Hard, Good or Easy. “Again” means you forgot, so the card comes back soon; “Easy” pushes the next review far out. The scheduler turns those grades into intervals so you don’t have to plan anything.
How to actually use it
Three habits make spaced repetition work. First, write good cards: one idea per card, phrased as a question you answer from memory (this is active recall — the two techniques are partners). Second, review daily; the algorithm assumes you show up, and a backlog is what makes people quit. Third, be honest when you grade — marking a card “Good” when you actually blanked just breaks the schedule.
Start small. Ten minutes a day on the cards that are due beats a three-hour binge before the exam, and it compounds across a whole term.
Spaced repetition from your lectures
MeetIT ships FSRS-4.5 — the same modern scheduler family behind today’s Anki — but builds the cards for you from the lecture you recorded, so you skip the slowest part. One “Study now” button covers an entire course folder, so your daily review is a single queue instead of a chore per deck.
And when a card comes up that you got wrong, you can jump straight to the moment in the recording where your professor explained it — a replay no hand-made deck can offer. Transcription and scheduling run on your own device, so your study material never leaves your laptop.
Frequently asked questions
What is spaced repetition?
A review technique that schedules each item to be revisited at increasing intervals — just before you’re likely to forget it — so material moves into long-term memory with the least total effort.
Is spaced repetition better than cramming?
For lasting memory, yes. The spacing effect shows that the same study time spread across sessions produces far stronger recall than massing it into one. Cramming only helps for the next day or two.
What’s the difference between SM-2 and FSRS?
SM-2 is an older heuristic that scales intervals by an ease factor. FSRS models the probability you’ll recall each card and schedules to a target retention, which is more accurate and means fewer reviews for the same results.
How is spaced repetition different from active recall?
Active recall is testing yourself; spaced repetition is the schedule for when to do it. You use them together — and MeetIT combines both, building cards from your lectures and scheduling them with FSRS.