Learning occupies a very important place in one's life. Your best efforts in learning may turn futile if the products of learning are not used by you as and when required. For making use of the material learnt, it must remain in your mind stored up somehow, to be used when the need arises. You are sure to have exclaimed sometime. "Oh! I don't remember", or "Oh, I am not able to recollect". Now these experiences are directly related to memory.