Kondo Audio Note Io ii+ Kondo AN S 7 II - Keep it or sell it?

Things simply keep accumulating. At the moment I have both these pieces lying around in a drawer. I am in a quandary, because it is simply a shame that they are not being used. I assume that they will not depreciate in price, but what are the chances that they will appreciate?  

To put it in other words: Do I try to sell them now, or do I leave them in the drawer?