Many students face the same challenge: they study hard for an exam, pass it, but weeks later, most of what they learned has faded from memory. This isn’t a question of ability — it’s simply how our brains work. The good news is that there’s an effective strategy to retain information over the long term: spaced repetition.

This method not only helps you remember facts for longer but also improves comprehension and mental agility. Below, we explain what spaced repetition is, why it’s so effective, and how to do spaced repetition correctly to make the most of your study time.

What is spaced repetition?

Spaced repetition is a study technique that involves reviewing information at increasingly longer intervals. The idea is to reinforce knowledge just before you’re about to forget it, helping to consolidate it into long-term memory.

This approach is backed by research in cognitive psychology showing that spreading out review sessions is far more effective than cramming all your study into one day.

In other words, instead of re-reading your notes for hours in one sitting, it’s better to review them several times over days or weeks, gradually increasing the time between each review. It’s not about studying more, but about studying smarter.

How does the forgetting curve affect studying?

The forgetting curve, proposed by Hermann Ebbinghaus, shows how our memory loses information over time if we don’t reinforce it. According to this theory, after learning something new, we can forget up to 70% of the material within 24 hours if we don’t review it.

Spaced repetition counteracts this curve because each review reactivates the information in our memory and strengthens neural connections. With each session, the time it takes to forget grows longer, until the knowledge becomes solidly stored and almost permanent.

Why does spaced repetition actually work?

The effectiveness of spaced repetition comes down to several factors:

  • Memory reactivation: Reviewing at spaced intervals forces your brain to retrieve the information, which reinforces the memory trace.
  • Better attention: Spacing your study helps you avoid mental fatigue and keeps your interest in the material high.
  • Long-term memory consolidation: Regular reviews help move knowledge from short-term memory into long-term storage.
  • Optimised study time: By focusing on reviewing content just before you forget it, you spend less total time memorising in the long run.

Advantages of using spaced repetition

Adopting spaced repetition brings clear benefits for learners of all ages:

  1. Greater retention of information: Avoids the need to constantly re-learn material you’ve already studied.
  2. Deeper learning: It’s not just about memorising — each review deepens understanding.
  3. Reduced stress and procrastination: Planning study and review sessions in advance helps you avoid last-minute panic.
  4. Flexibility: Works with any subject and format, from vocabulary to complex maths formulas.
  5. Better exam readiness: Knowledge stays accessible for future assessments and practical situations.
  6. Improved study habits: Encourages consistency and a long-term approach to learning.
  7. Applicable at any stage: Useful for school pupils, university students, or adults learning new skills.

This kind of strategy can be especially helpful for students in the final years of secondary education, who want to consolidate their learning before facing demanding exams such as the IGCSE.

How to do spaced repetition

While the concept is simple, applying spaced repetition effectively requires organisation, consistency, and some small adjustments as you go along.

Organise your study material

Before starting, break your content down into topics or small blocks. This makes it easier to review and avoids overwhelm. You can use outlines, flashcards, or digital tools to structure the material.

Where possible, turn content into active prompts rather than just reading it passively. For example, instead of reading a definition, try to write it in your own words or explain it to someone else. Active recall significantly boosts the impact of spaced repetition.

Schedule reviews of what you have learnt

The heart of this technique is your calendar. A simple example of review intervals could be:

  • First review: 1 day after learning the content.
  • Second review: 3 days after the first.
  • Third review: 1 week later.
  • Fourth review: 2 weeks later.

After reviewing, extend the interval. Tools like Anki, Quizlet, or Notion can help you automate reminders and track your progress.

Monitor your progress

Not every topic needs the same number of reviews. Keep notes on which areas you’ve mastered and which still need more work. This allows you to focus your time where it’s most needed.

Make adjustments to your plan

Spaced repetition isn’t a rigid system. If a topic is particularly challenging, move its review forward. If you can recall something easily, increase the gap before the next review. The key is adapting the technique to your actual needs.