There is so much to be considered when shooting expired film and rules of thumb for how long a film is expired and whether it is good to shoot don't work. In general, roll films stand up better than cassettes. B&W films better than color, films stored cold better than hot, Kodak better than Fuji, negative better than transparency. Add to that, is the person shooting expecting a pristine image or are they excited about getting a unique distressed look.
Regardless...fun question and I'm interested to see the responses.
For those that are thinking of shooting expired film here's a fairly useful link regarding specifics about expired film....
http://www.filmrescue.com/qualities/factors/