You've certainly used them in the past, but you may not have been using them in a way that maximized their benefits. Behold the Leitner system, which provides more structure to the tried-and-true practice of studying with flashcards and might be the jumpstart your studying needs. This system was devised by science writer Sebastian Leitner in 1972, which is why he gets the honor of having it named for him. For the first few decades of its use, it relied solely on on physical tools: flashcards and boxes. If you answer cards from Box 2 correctly, they’ll go to Box 3, which in this example is your “weekly” box.