Hi, I keep all mine. If you only have a few then you can keep track of them in one of the cases (I do use one in the car). But when you have hundreds...I have them on shelves like a library. Same for LPs and cassettes.
Yea, I understand if you have a case for the car and you keep the CDs in there. But I don't understand why some people then dispose of the album cases. I'm like you and believe they should go on a shelf like books.