Can I count in months or year ?
Another thing you should consider for long term storage is moisture. To prevent oxidation and other negative things that can happen to your chemicals when exposed to moisture long term, you should get a desiccant (silica gel) and put them in the vicinity of your substances.
Definitely. I'm aware of the moisture issue and use dessicant whenever I store drugs. That's why I'm curious about freezing the stuff. It would add to the likelihood of moisture exposure but reduce temps, so there's a tradeoff. What do y'all think about this? Is 2C sensitive enough to temperatures to make this tradeoff worth it when we're talking about decades of storage?