Spaced repetition, explained simply

The forgetting curve

Learn a fact today and you will forget most of it within a few days unless you meet it again. Each time you successfully recall it, the memory decays more slowly, so the gap before the next review can be longer. Review too early and you waste effort on something you still know. Review too late and you have forgotten it and have to learn it again.

Spaced repetition just means spacing your reviews to land in that sweet spot: today, then in a few days, then in a week or two, then a month. Each successful recall pushes the next review further out.

Why it beats cramming

Cramming loads everything into one session the night before. It works for about a day, which is why it feels effective, and then it drains away, which is why you remember almost nothing a week later. Spaced reviews cost far less total time and leave the knowledge in place for the actual exam, not just the morning of it.

The other half: active recall

Spacing decides when you review. Active recall decides how. The reviews only work if you actually try to retrieve the answer from memory before checking, rather than rereading it. A flashcard does this naturally: you see the question, you struggle, then you flip. Rereading a summary on the same schedule does much less.

How to do it without a spreadsheet

1. 1Put what you need to remember on flashcards, one idea each.
2. 2Each day, review the cards that are due. Mark each one as known, unsure, or wrong.
3. 3Cards you got wrong come back soon. Cards you knew come back later.
4. 4Trust the queue. If today's stack is short, you are done; do not review ahead for the sake of it.

You can track all of this on paper with the Leitner box method, moving cards between boxes by how well you know them. It works, but it is fiddly. Software does the scheduling for you, which is the point of the daily due queue in the Orpheus flashcards tool: open it, clear what is due, close it.

Start early, keep it short

Spaced repetition needs time between reviews to work, so its one real requirement is starting weeks before the exam, not days. Ten honest minutes a day, most days, will beat a six-hour panic the night before by a wide margin.