Retention Engineering — Spaced Repetition & Active Recall

Operationalize the two highest-evidence learning methods — retrieval practice and spaced repetition — inside your teaching artifacts, and internalize the reframe: retention is not the learner's responsibility; it is the teacher's design responsibility. Retention engineering is cache-invalidation discipline. The forgetting curve specifies the TTL; spaced repetition is scheduled refresh; retrieval practice is the read that catches stale data before it causes a downstream failure. "Review this on your own time" is the teaching equivalent of "the user will manually clear their cache" — a sentence you would never let into a design doc. Engineers who can reason about cache invalidation can absolutely reason about memory invalidation; the discipline is simply to accept that the cache is your responsibility, because you wrote to it.