Spaced repetition stops the forgetting curve
The amount of time needed will differ for each person. Schedule time to review content every day.
One method is known as the leitner-system, which is a simple form that can be adopted with index cards.
Forgetting curve was discovered by Hermann Ebbinghaus.
references
- https://notes.andymatuschak.org/Spaced_repetition_memory_system
- https://gwern.net/spaced-repetition