I once told someone that you can never have too big of a shop. I have been both wrong and right in that statement. If you are just storing things in it and utilize ocasionally, big is fantastic.
I converted my wifes horse barn into a bow shop and got too busy to finish insulating it. It is now too big and expensive to air condition or heat. My wife has somewhat grown used to the idea and helps me clean it (or I should say cleans it for me). Even though the shop is big though, (24x70) there is never enough wall space for shelves and racks and such.
Oh well, I've never had enough time to build and organize anyway.
BigJim