I ought to expand something that doesn't really change my
answer: I've been hearing longer estimates of how long the virus can survive outside a living host. Apparently on cold, dry, extremely hard, surfaces (including metal and glass) the virus can survive up to nine days, although perhaps not in the quantities needed to infect someone. A credible-sounding expert who got paraded across one of my screens today was saying that, in practice, she'd be careful of hard smooth cold dry surfaces for about 72 hours, and something softer and more porous (like
cardboard boxes) for about 24 hours.