The dry chemicals all last ages. Ferric Oxalate does go off when it's in solution. The metal salts (Pt and Pd) last forever in solution (with some qualifiers about how they're stored). Personally I wouldn't trust anything other than the Pt/Pd solutions. Ferric Oxalate is much, much cheaper than Pt/Pd so it's not worth risking a single failed print because of stale Ferric Oxalate. And mix fresh EDTA because it can take several years to discover that your EDTA was exhausted – and by that time your print is ruined.
Thanks! The ratios helped a lot and will be good for comparison to others input. Unfortunately all the chemicals are at the photo lab on campus. I'll have to do all the work there and definitely won't be able to take anything home. I also need to ask the head lab technician when the chemicals were purchased. I'm mainly diving into it because if they belong to the photo department, then it's free for me to use them. If the chemicals are bad, I'll probably end up buying some palladium solution to work with since it's much cheaper than platinum. I probably won't be heating any of the solutions or working with this stuff extensively. I'm just a college kid looking to experiment a little Although I am taking a class called Advanced Black and White Photography and our final project of 6 photos is approaching. Maybe if the platinum printing works out, I'll do it for my final