Revision — memory that fades like yours

FSRS-style retention, so chapters return before they're gone.

Every measured chapter carries a retention estimate on a power-law forgetting curve — the shape large-scale spaced-repetition benchmarks find actually fits human recall:

Stability S scales with how well you know the chapter — stronger memories decay slower. When a chapter's retrievability falls below 0.85 it surfaces in Revise with its freshness percentage, and the daily quiz preferentially rotates fading chapters back in. Nothing nags on a schedule; things return when your memory of them is actually at risk.