About twenty years ago, I did a four month stint backpacking round Eastern Europe and then six months in Asia. Took a bit of persuading the gp to give me a script for 4 and then 6 months worth of insulin. It's so long ago that I can't even remember the names of the insulins.
Maybe modern insulins are more delicate now, but I was still using the same insulin supply at the end of both trips as I was at the start.
None of it had been in a frio or in a fridge the whole time, just carefully packed in the backpack and stored in a dark space in hostels.
I think the 28 day thing is the manufacturer's lawyers being paranoid about their client being sued. I think they last well over 28 days.
But, like I say, maybe modern insulins aren't as tough as 20 years ago. I don't know.
Even if they do wimp out after 28 days, it's not like they just suddenly stop working. The efficiency slowly degrades in stages, so you might need to inject a little more for the same effect, so there will likely be plenty of safe room to decide, ok, this is tailing off now, better bail out to the nearest small town and see if I can buy some.
It's not going to be like one day it works and the next it doesn't. There will be plenty of time to find some more, even if it will cost you a buck.
If I was doing another long trip, I'd do the same again - take several months supply, so I at least know I've got it all there, but have a back up plan to get more if it fails: depending on where I'm going, could be insurance, or consul/embassy details to steer me through local systems, or dollars.
Looks like a fantastic trip ahead of you!
