Spaced practice

Spread study over time instead of cramming it into one session.

Why it works

Letting some forgetting happen between study sessions makes the next retrieval more effortful, and that effort is exactly what strengthens the memory — re-learning something you have partly forgotten builds a more durable trace than restudying something still fresh. Massed practice feels efficient because everything stays fluent, but that fluency fades fast after you stop.

How to do it

1. Break study into multiple shorter sessions separated by days rather than one long block.
2. Deliberately revisit material after you have begun to forget it, not before.
3. Lengthen the gaps between reviews as the material becomes more secure.

Evidence

The spacing effect — distributed practice yielding stronger long-term retention than massed practice — is among the most robustly replicated results in learning research, confirmed across many studies and a large meta-analysis. A large-scale study mapping retention against the study gap (Cepeda et al., 2008) found the optimal gap scales with how long you need to remember, grounding the "expanding intervals" guidance in measured data rather than intuition. (rct)

The best gap depends on how long you need to retain the material — longer retention goals call for longer spacing — so there is no single optimal interval.

Sources

• Cepeda et al. (2006), meta-analysis of distributed practice, Psychological Bulletin
• Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.
• Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H. (2008). Spacing effects in learning: A temporal ridgeline of optimal retention. Psychological Science, 19(11), 1095–1102.
• Kang, S. H. K. (2016). Spaced repetition promotes efficient and effective learning: Policy implications for instruction. Policy Insights from the Behavioral and Brain Sciences, 3(1), 12–19.

Common mistake

Cramming the night before because it boosts short-term performance, while sacrificing the durable retention that spacing would have produced.