Flashcards are small cards containing information that are used as an aid for learning. They can contain words, numbers, or pictures. When making flashcards, one should choose an important category of information, select the most essential details within that category, and personalize the cards. Flashcards are an effective and cheap way to teach and study, and allow learning in short bursts of time. However, some topics are not well-suited to flashcards and they can become boring with repetitive use. The key to using flashcards effectively is to retrieve information without cheating, shuffle cards frequently, and repeat viewing each card at least three times. Several apps exist to help create and study with digital flashcards.