FINAL School Supplies

You know when in the beginning of the year you get a list of school supplies that you are going to need for every class well you don't always use everything that i s on it lol. Then it comes to the end of the year and you don't have it any more what happened to it. Do you realize what has happened to you let people borrow or you forget it in a class. I have always thought about it you know like why does this happen it is true that you cant have what you have had once and have  again but this is something that has bothered me through the school years ?:)