The Anki problem
The Anking deck has 25,000+ cards. Without scheduling tuned to recall history, you spend weeks reviewing cards you already know and lose cards you almost remember. When the daily queue creeps past 500, burnout follows. FSRS — opt-in in Anki since version 23.10 (October 2023) — has published research showing roughly 20–30% fewer total reviews to reach the same retention versus SM-2. Over six months, that compounds into hundreds of hours back.