How long can you keep canned sodas that have not been opened? My grandson would not drink one that had an expired date.
Soda's not like milk that'll spoil after the expiration date. From my own experience, the worst that'll happen is that it may not taste as good, but that's months after the expiration date. I'm not sure if that's the case with diet sodas as it contains different chemicals, but for regular sodas, it's still consumable.
Canned soda usually lasts 6 months past the printed date, it may be flat but it won't be bad!