The science behind spaced repetition in plain terms: why spacing review out beats rereading or cramming, how an SM-2-style scheduler decides when to show you a card, and how to use it without an app.
Rewatching a video feels like studying, but the evidence for active recall, testing yourself instead of re-exposing yourself to the material, is much stronger. Here's the actual difference and how to build recall into a video-based study habit.
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