The Tri-X 320 arrived at the weekend and it expired in 2006. It's been kept in a fridge since but, from what I can gather, B&W film tends not to go off as badly as colour film. Nevertheless, I'll be shooting it at ISO 160 to be on the safe side and, as it's purely a bit of fun, I won't be using it for anything where the end result is important to me - i.e. it is film to be "wasted".