Most students re-read their notes the night before an exam and wonder why nothing sticks. The problem isn't effort — it's timing. Spaced repetition is a memorisation technique based on a simple but powerful insight: your brain retains information far better when you review it at increasing intervals over time, rather than all at once.

This principle, known as the spacing effect, was first documented by psychologist Hermann Ebbinghaus in the 1880s, and has been replicated in hundreds of studies since. Yet most students still cram — the least efficient way to learn.

Why Your Brain Forgets

Ebbinghaus mapped out the forgetting curve: without any review, you forget roughly 50% of new information within a day, and up to 90% within a week. Every time you successfully recall something, however, the forgetting curve flattens — the memory trace strengthens, and you can wait longer before the next review without losing it.

Spaced repetition exploits this by scheduling reviews at precisely the right moment — just as you're about to forget. Each successful review pushes the next one further into the future. After five or six reviews, something moves from short-term to long-term memory and you may only need to review it once a month to retain it indefinitely.

How to Get Started with Anki

Anki is a free, open-source flashcard app that automates spaced repetition scheduling using an algorithm called SM-2. It's the tool of choice for medical students, language learners, and anyone who needs to memorise large volumes of information reliably.

Here's how to start:

  1. Download Anki at ankiweb.net — it's free on desktop, and AnkiWeb syncs across devices.
  2. Create simple cards. One concept per card. The front should be a question or prompt; the back, the answer. Avoid putting multiple facts on one card.
  3. Add cards as you study, not after. Make cards while reading or attending lectures, when the material is fresh.
  4. Do your reviews every day. Consistency matters more than session length. Even 10 minutes daily compounds dramatically over a semester.
  5. Rate each card honestly. Anki gives you four options after each card: Again, Hard, Good, Easy. Be honest — grading cards as Easy when they weren't cheats the algorithm and yourself.

What Makes a Good Flashcard

Most students create cards that are too complex. A good Anki card follows the minimum information principle: it tests one, and only one, piece of information. Instead of "List all the causes of World War I", create separate cards for each cause.

Add images where possible — visual encoding significantly boosts recall. Use cloze deletions (fill-in-the-blank format) for definitions and formulas. Write cards in your own words, not copied from a textbook.

Building the Daily Review Habit

The most common mistake with Anki is skipping days. When you skip a day, reviews accumulate. Skip a week, and you face a daunting backlog that most people never recover from. Treat your daily review like brushing your teeth — non-negotiable, brief, and immediately rewarding.

A sustainable starting point: spend 15–20 minutes each morning on reviews before adding new cards. Keep your new-cards-per-day setting modest (10–20) until you find your comfortable pace. The queue will grow gradually, but so will your retention.

Beyond Anki: Low-Tech Spaced Repetition

If you prefer physical flashcards, the Leitner system works on the same principle. Use five boxes numbered 1–5. New cards go in Box 1. Review Box 1 daily, Box 2 every other day, Box 3 weekly, and so on. Cards you get right move up a box; cards you get wrong drop back to Box 1. It's simple, tactile, and effective.

The Bottom Line

Spaced repetition isn't a shortcut — it's a smarter use of the time you're already spending. Students who build a consistent daily review habit typically retain 80–90% of their material after six months, compared to 20% for those relying on cramming. The investment is small; the returns are extraordinary.