One of our cats (Haru) chews small wires, and recently chewed through the USB Type A to barrel connector cord for my LED reading light. No biggie, I thought, I'll just buy a replacement for it, and move on. But wait, an entirely new reading light is just as cheap! I'll buy that so I'll have two, and I won't have to worry about buying the wrong connector.
When the new reading light arrived, I found out it now used a micro USB connector instead of the barrel, and more importantly, wouldn't run off of the battery. Some disassembly, and the reason became pretty obvious. The battery was slightly bulgy, had almost no resistance, and had zero voltage. All signs of a battery which shorted out at some point very early in its lifetime.
Luckily, I had a working battery from the older light... so why not swap? Some dodgy soldering work later, and voila! One working light with more universal connectors and some extra parts. My rudimentary soldering and electronic troubleshooting skills keep coming in handy.