Spaced Repetition: Why It Works and How to Use It Without Fancy Apps

Memory is not a hard drive. It is a leaky bucket. The trick is to top it up at exactly the right moment — not too soon (waste of time) and not too late (you've forgotten everything).

That is what spaced repetition does.

The forgetting curve, in plain English

After learning something, your retention drops fast for a day or two, then levels off. Each time you successfully recall the thing, the curve flattens. Review it at the right interval and you can hold information for years with five minutes of work a week.

The intervals that work

• Review on day 1
• Review on day 3
• Review on day 7
• Review on day 14
• Review on day 30
• Review every two months after that

You do not need to track this manually. Flashcards uses the SM-2 algorithm to push each card at the right gap.

Three rules

1. Make atomic flashcards. One idea per card. "Capital of France: Paris" is good. A whole essay on the French Revolution is bad.
2. Active recall, always. Read the front, try to answer, then flip. Never just stare at both sides.
3. Review even when you are confident. That is when the curve does the most work.

What to put on cards

• Vocabulary (any language)
• Formulas + when to use them
• Historical dates that matter
• Definitions
• Code syntax

What not to put on cards: anything you do not understand yet. Cards reinforce understanding, they do not create it.