Istudies have shown that epinephrine autoinjectors are good for up to four years, with something like 80% potency, but I would never let a primary device expire.
Someone in my local allergy group is in contact with Kaléo and in discussions about bringing them back to Canada. Apparently the $300/device cost is too high for insurance companies here to cover. (That is the cost she mentioned, in Canada.). The new robotic manufacturing method has made these much more expensive to make. So she is building a case from local families to bring to Kaléo showing demand here... But I doubt many people will pay $600 per set, when people already complain that $100 is too much for one EpiPen, and many people here still don't carry two. Me, I'd pay the $600 for infinitely more comfortable devices when training every day - seriously. Allerject fit in all my pockets, EpiPens fit in NONE, not even my cycling jersey, and waist pouches are starting to injure my back when running long distances.
This link may be helpful here with regards to temperature:
https://community.kidswithfoodallergies.org/blog/researchers-review-effects-of-heat-cold-on-epinephrineYes, yes... I know the source, but it's a good article.