I personally only use sleeves like this for temp stuff or if im giving something out. I dont think there ideal for any sort of long term storage. I do how ever have some stuff in these which are sitting uprit in a draw mainly do to the fact i have a newer version of whats on the disc.
Most here will say for long term storage use dvd or cd jewel case's. I personally have wat too meny discs to do that i do how ever want to keep everything aslong as possible, so im in the process of putting discs in the DJ Style case. I do keep some stuff in cd jewel case's. If how ever i burn something thats important then in will go in a case no question.