I rarely have sold anything. Most of what I have, I have accumulated over a period of 28 years or so. Most of what I have sold has been redundant. Where there was a time that I could use 2 Juno-60's DCB'd together, multitracking and sequencing made a second Juno redundant and it was sold to a friend.
I also like to have everything set up so that I can just turn it on and play it. If it is in "storage" or in the corner collecting dust, I question why I should have that piece of gear in the first place. Although the studio is a collection, I don't consider myself a "collector", but rather a musician that likes to have options open. Gear is always placed in a position where it is ergonomically useful. Sequencers are placed next to the pieces of gear that they will be most likely used with. To me, this is a very important detail in studio organization.