My current darkroom is in my basement, purpose-built. It's kind of small, about 7'x8', but it gets the job done admirably. I can do enlarging up to 16x20 from 35mm-4x5 negs, and alt process to 11x14". All my previous darkrooms have been various bathrooms in the apartments I've had. I had an IKEA cart that I used to put the enlarger on top (and was the perfect size for the baseboard), and the Nova vertical processor underneath, so the whole kit could be wheeled in and out in a few minutes. When not in use, the remaining kit could be wheeled into the walk-in closet in the master bedroom for storage.