I know the stop bath will last forever. If you're unsure, just use plain white vinegar diluted 50-50... it will do the same thing.
Rodinal, as long as it isn't mixed should last pretty much forever. It's the oxygen contained in the water in soluble form that kills developers. Since Rodinal doesn't contain any, that's why I think it will be good. If in doubt, test it on a bit of unexposed film...
As for the fixer, the only way to know if it's still good is to do a drop test. A piece of film leader is perfect for that. Just fix for double the clearing time
But overall, I think you should be OK with the stuff.