Cramming works. Just not for long. If you study a topic intensively the night before an exam, you will probably be able to recall enough to pass. But within a week, most of that information will be gone — because the brain treats things reviewed only once as low priority. Spaced repetition is the opposite approach: review material at increasing intervals over time. Review it the day after you first learned it. Then three days later. Then a week later. Then two weeks later. Each review resets the forgetting curve and strengthens the memory a little more. The same total hours of study, distributed differently, produces dramatically better long-term retention. Spaced repetition is not a revision technique — it is a different relationship with learning time altogether.