Spaced repetition is a study method that schedules repeated retrieval over time. Instead of rereading everything on a fixed daily schedule, a learner reviews an item, reports how recall went, and lets a scheduler choose a later date.

Research on the spacing effect supports distributing practice rather than concentrating it in one session. It does not promise a particular grade, retention percentage, or permanent memory for an individual learner. Source quality, understanding, the review task, and continued practice still matter.

What a scheduler does

A spaced-repetition system stores a due date for each card. After a review, it uses the selected rating and the card's current state to compute a new interval. Successful reviews usually produce longer intervals; a failed recall usually returns the card to a shorter one.

Mnestica uses four ratings:

  • Again: you could not recall the answer.
  • Hard: you recalled it with substantial effort.
  • Good: you recalled it normally.
  • Easy: the answer was immediate.

Mnestica's flashcard scheduler is SM-2-inspired. It uses intervals, ease factors, and fixed learning-phase rules. It does not predict the exact moment a person will forget.

What spaced repetition does not do

Scheduling cannot replace first understanding. It also cannot rescue an ambiguous or overloaded prompt. A useful card has a clear cue and a checkable answer. If a card keeps failing because of its wording, changing the prompt can be more useful than repeating the same item.

Consistency helps keep a due queue manageable, but missing a day is not a failure condition. The queue remains available and overdue cards can be worked through later.

How Mnestica extends the card loop

Mnestica connects flashcards with notes and reading items. Memory Studio shows computed queue indicators and open care cases. The on-demand Memory Coach can suggest rewriting, splitting, suspending, or retiring a card. You preview and approve any mutation; the coach does not silently edit cards.

These tools provide a source-to-review workflow and operational scheduling signals. Their purpose is to help a learner decide what to review or repair next, not to certify a learning outcome.