# Training half-life

> How fast a skill decays after training, without reinforcement.

Source: https://iambenschmidt.com/lexicon/training-half-life/ · 2026-05-22


**Training half-life** is how long it takes for half of what someone learned in training to leak back out, with no reinforcement.

It is shorter than anyone selling you a workshop wants to admit. The forgetting curve is real and it is steep. One-and-done training has a brutally short half-life; spaced, low-dose practice is the only thing that extends it. The slide deck is not the intervention. The reps after it are.

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## Related Reading

- [Learning & AI](https://iambenschmidt.com/essays/learning-and-ai/)


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