" Ebbinghaus posited that memories will fade or not be retained if there is insufficient rehearsal and practice. He estimated that people typically remember only 50% of newly learned information three weeks after exposure, and they remember only 10% eight weeks after exposure. Additional studies have confirmed that it’s possible to retain up to 80% of newly learned information if you review and rehearse it within twenty-four hours after exposure. "

― Peter Hollins , Learn Like Einstein: Memorize More, Read Faster, Focus Better, and Master Anything With Ease… Become An Expert in Record Time (Accelerated Learning)