If you care about avoiding "processed foods" in other domains and are consuming shrink-wrapped bars with a shelf life of 2+ months: here be dragons!
I store ours in a glass container the refrigerator, where they're individually wrapped in butcher paper. I'd consider them good outside of the fridge (in the paper) for 32 hours, inside the fridge for a week or two. Making a batch takes about 10 minutes + overnight refrigeration, and the recipe is trivial to scale-up/down in size.
They're certainly not as convenient or robust as shrink-wrapped lara bars, but we're not frequently in situations where the diff disappoints, ymmv.