keep the cams out of the sun and heat and they should be ok for 5-10 years after the date. I know a photographer who only uses expired film and she has had only 2 rolls fail out of thousands.
for the price its worth keeping one in the car.
Film pics stand up very well in court, but Digital could be dodgy due to ease of editing, film can be edited but its a lit harder to develop, edit, re-expose to a 2nd film even more so if the film is still in a disposable cam.
just dont leave it in your boot if Snell is following you