We have backup batteries for everything we own. We get 'em at CostCo in industrial-sized packages, something like 4 dozen for the AA batteries. I bought a bunch of the LR44 batteries for my mini LED flashlights and digital electronic calipers. 40 of them for $8 and free shipping from eBay. They are a buck or two each at the hardware store, depending on the brand. They are near the end of their shelf life- best by 2020. I still have 10 left, after a little less than a year. So I didn't mind that, as they were so cheap.
If you get to thinking you’re a person of some influence, try ordering somebody else’s dog around.