repetitio est mater studiorum: http://www.supermemo.com/english/princip.htm "Have you noticed that soon after learning a new study material you remember very little of it? The less you have a chance to rehearse what you have learned, the greater the speed with which the newly acquired knowledge evaporates from your memory. It has long been known that repetitio est mater studiorum (Latin: repetition is the mother of learning). In other words, the best way to remember is to make repetitions of the learned material. However, you might find it quite frustrating when you have to repeat old subjects while your teachers or supervisors still want you to know more and more new material. When are you supposed to find time for both? Usually, you find a solution in-between. You spend most of your time learning new things, forgetting what you have learned earlier, and rehearsing only material that is needed for current exams or other emergencies. The net result is disastrous! Most of your time goes to waste as you forget most of the learned knowledge. Naturally, you gain general understanding of the studied material, but understanding is also based on memory traces and is equally volatile. It is only a question of time when you irreversibly lose most of your investment in learning. Is the above presented situation inevitable? The pressures of the day do not really let you rehearse what you have learned earlier. The educational systems throughout the world are organized in a way that penalizes those who do not master the new material. You are pushed into a nonsensical situation. You are truly forced to waste your time and ... waste your life. "