Why words fade so quickly
After a first encounter, a word is still fragile in memory. Without a timely return, the trace weakens fast. That is why many learners feel they almost know a word but still fail to recall it when reading.
Spaced repetition is based on a simple idea. Every successful recall makes a word more stable, so the next interval can become longer. At first the word comes back often, later less often.
Why this saves time
- fewer unnecessary repetitions
- more attention on words that actually need help
- steadier vocabulary growth
- less random review
What FSRS adds
FSRS uses your response history to estimate memory state and schedule the next review window. That makes the pace more flexible than a fixed rule for every word.
Easy words stop interrupting too often, while difficult words do not disappear for too long. Each word gets its own rhythm.