Ideally, you should get a 30-day optical/mechanical return privilege with any camera you buy from a reputable source. That would give you time to try the camera and have a repair person give it a once-over for you. I would recommend a tuneup for any Hasselblad purchased used unless the seller certifies it's had a recent checkup. A qualified technician will tell you what shape it's in. A Hasselblad is a precision instrument. It's more like owning a Porsche than a Ford. Plan on occasional maintenance for camera body, lenses and backs, depending on how much you use them. They're great cameras, and I love mine. With care, they will last many years.

Peter Gomena