I do have a lot of 12" deep bookcases, and they are packed two rows deep and two high with jewelcases/digipaks, and many maybe most of the jewelcases are thin case doubles, so for example two Ellington cds are in one double jewelcase, two Albert Ayler cds are in one double jewelcase, two Carmen McRae cds are in one double cd jewelcase, etc.* (I buy tons of those two cd inserts). I have as many of these bookcases as my wife will allow in the house, which is not as many as I would like.
I also have a large climate controlled storage unit for discs, books, instruments. . . that has gotten very expensive and I have been "instructed" to empty it. . .that is hard for me but I have begun doing so. Will take a while though, especially as my wife doesn't like me to be away from home long. Sigh.
Over the years (and in married life) it certainly has become a problem. I wish I liked streaming/files etc. but I don't. And much of what I have and want is not easily available that way.
As for organization there is not that much. There are three labels I have sort of completely together (but not necessarily organized within the togetherness): Blue Note, Impulse, Bethlehem. I have most of my Miles Davis all together. The rest is sort of willy-nilly. My memory is very good, and I remember where things are for the most part, and I go through areas of the collection now and then to refresh memory.
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and