The old books can help us in many ways .as if we may refer them for any doubt as they are related to the next class. as we studied last year we can not remember all the things. so,these books will help us and also these books helps us in doing our projects. this causes alot of damage to us .

Some of the problems caused by  this unnecessary disposal is that when they move on to their next grade, they would lack materials for freshening up on prerequisites and thus would be wishing that they hadn't thrown away their books. Also on a more personal note, mind you that this is just a humble suggestion, why not give your books away to people who need them but just can't afford them?