My assumption is that when the zombies start doing their thing and the online ordering of elastics stops, you could probably loot a few therabands from a sporting goods store to build up your supply, if its low. then you will have whatever the life expectancy of the rubber is to figure it out. If the bands become unusable in three years without proper storage, then you still have that amount of time to figure out how to get more or do without. I have no idea how long that would be. but I assume that if you have a pretty good stash available locally, it will be long enough that you should have bigger stuff to figure out for a while... But that being said, I definately appreciate wanting to be able to do for myself if the need arises.