What is spaced repetition?

Spaced repetition means reviewing material several times, with longer and longer gaps between reviews, instead of studying it all in one go. For example: review new notes the next day, then three days later, then a week later, then before the exam.

Why it works

Learning research has found again and again that spreading study out leads to better long-term memory than cramming the same total time into one session. A large review of this “spacing effect” by Cepeda and colleagues (2006) found the benefit across hundreds of studies.

Each review also works better if you test yourself rather than reread: trying to recall the answer strengthens memory more than looking at it again.

How to use it

1. After a lesson or reading, write short questions about the key ideas.
2. Answer them from memory the next day.
3. Review again a few days later, and again a week later.
4. Spend more time on the questions you get wrong, less on the ones you know.

Flashcard apps automate the schedule, but a simple plan in your calendar works too.

In Thendoo: plan review sessions as repeating tasks or time blocks, keep questions in a Doc per course, and use the exam study plan template to spread reviews across the weeks before an exam. Read more in How to study from lecture recordings.