Fixed vs expanding intervals — which spacing pattern should you use?

Expanding intervals are the classic pattern, but the headline finding is that ANY spacing beats massing (cramming).

• Expanding: review after ~1 day, then a few days, then ~1 week, ~2 weeks, ~1 month — each gap longer than the last, tracking your slowly growing durability.
• Fixed: review at a constant gap (e.g. every 3 days). This still works well.

Both comfortably beat studying the same item repeatedly in one sitting. So don't agonise over the exact schedule: the big win is putting gaps between reviews at all. Expanding is a sensible default because your memory does get more durable with each success.