When I bought this place it had no shed, so I ordered an American barn, 18.5 x 12.5 with a mezzanine floor. Bearing in mind I had no tractors or engines at that time, only cars and motorbikes. A couple of days later I thought, "No-one needs a shed that big", so I cancelled the last bay, cutting it down to 15 x 12.5. Then I moved in, built a 3.5 x 9.5 annex on one side, then added a 4 bay tractor shed down the back.
Just proves, the more shed you have, the more "stock" you keep.