Gurudev, I remember the story of a movie I saw ten years back. Yet I forget the knowledge I heard yesterday. How come?
Never mind. Knowledge will come from time to time when it is needed, and then you forget it also. Forgetfulness is also bliss. You should not carry all the knowledge; it is too heavy on the head.
You know, knowledge is also like soap. In the Bhagavad Gita, it is said, 'Na hi jnanena sadrusham pavitram iha vidyate. Tat svayam yoga-samsiddhah kalenatmani vindati'. (4.38)
You put on the soap and then you wash it away. So, take the knowledge, use it and then become hollow and empty. You become free from it. And when it is needed, it will surely come to you.