Spaced Repetition

---
name: spaced-repetition
description: Schedule review at increasing intervals so knowledge is retained with minimal total time. Use when you must remember material long-term rather than pass an immediate test.
---

# Spaced repetition

Forgetting is exponential and predictable, and reviewing just before you
would forget resets the curve. This makes retention a scheduling problem
rather than an effort problem.

## Method

1. **Review at expanding intervals.** Days, then weeks, then months,
   since reviewing material you still know well wastes the session.
2. **Test recall rather than rereading.** Retrieving from memory
   strengthens it; rereading produces familiarity that feels like
   knowing and is not.
3. **Make each item atomic.** One fact or one relationship per card,
   because compound items fail partially and cannot be scheduled
   sensibly.
4. **Write items in your own words.** Copied text is recognised rather
   than understood, and the writing is itself the learning.
5. **Reschedule by difficulty.** Items you fail return sooner; items you
   find easy stretch further out, which is what makes the total time
   small.
6. **Prune ruthlessly.** Material you no longer need should leave the
   rotation, or maintenance grows until you abandon it.
7. **Pair with application.** Recall supports understanding but does not
   create it, and applying the knowledge is what makes it usable (see
   deliberate-practice).

## Boundaries

Spaced repetition suits discrete facts and vocabulary far better than
skills and judgement. It requires daily consistency, and lapses produce
a backlog that discourages return. Memorising material you could look up
is often not worth the time.