A lot depends on how the film has been stored. I was once given a huge lot of 40-50 year old Tri-X. I tried developing an unexposed roll, and got a 100% black strip of film, edge to edge. Some people get images out of old film. I might hold hope for 40 year old slow films, but not much for Tri-X. It's always worth piggybacking an unexposed strip of the old film on one of your "normal" rolls, though.