For a small shed or shop, a 2–4 person crew with basic hand tools can raise a quonset hut in a day or two , that’s been true since the original WWII design. For anything larger, or anything requiring precise wind/snow engineering, many buyers who start as DIY end up bringing in a crew partway through. Panel alignment and seam sealing matter more than the marketing suggests; get it wrong and you’re dealing with leaks and voided warranties later.