My husband's "shack" as they call it in the ham radio world, is in the back of the detatched garage. When we first moved in here, we had five young kids so every little inch of space was needed, except for one tiny upstairs bedroom. So, he took our double garage (really long) and built a very nice insulated room at the back with a steel door and heat and ac. Then, I eventually started taking over the small extra bedroom upstairs as I started sewing more.
When MIL moved in with us 5 years ago, I lost my room. I then started taking over the really wide hallway in the basement just to store everything quilty in containers. As the kids started moving out, my mind started scheming. As soon as one of the two bedrooms was empty, I was in there, that night cleaning carpet and doing touchup painting. I was in there by nine the next morning-poor kid didn't think I loved him!!!
Since then, I moved into the double-room rec room and finally landed in the largest room in the basement. Since MIL can't do stairs, I have bought another quilting table for upstairs (so I can be with her when she is awake) and a plug in doorbell for the sewing room for those moments when I need to go downstairs for a few while she is awake.