Use spacing as a control loop, not a sacred calendar

When it fits

• You want concrete review intervals but do not want to pretend one schedule is scientifically optimal for every item.

When to avoid it

• The example 1-3-7-14-30 sequence is an editorial starting heuristic, not a finding that these exact days are optimal.

Why it matters

Space successful retrievals farther apart and pull failed or effortful items nearer. As a practical starting heuristic, a newly learned high-value item might be checked around the next day, then after roughly 3, 7, 14 and 30 days, with longer gaps after stable success. Treat those numbers as defaults, not evidence-backed commandments. The research supports spacing and longer gaps for delayed retention, while equal and expanding schedules perform similarly on average.

Steps

1. Fast, correct recall with appropriate use: Increase the next interval substantially.
2. Correct but fragile or slow recall: Increase only modestly and keep a productive prompt.
3. Wrong or absent recall: Relearn now and schedule a nearer retrieval.
4. Stable recall after long delay: Move to maintenance intervals or retire from frequent review.

Check your result

Intervals change in response to retrieval quality and the desired retention horizon.

Keep this limit in mind

• The example 1-3-7-14-30 sequence is an editorial starting heuristic, not a finding that these exact days are optimal.

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