In 2006, they recalled a bunch of Dell laptop batteries because they were exploding or something. They told everyone to check the little numbers on their batteries to see if they needed to be recalled. Of my two batteries, one was part of the recall. So I just stuck it in my laptop bag and used the other one. It's nice having two batteries. I used to switch them out sometimes if one ran out and I couldn't plug into a wall socket for whatever reason. But since 2006, I've just been using the one, and the other just sat in my bag. I don't know why I never sent it in to get a free non-exploding replacement. To be fair, I did forget about it soon after, and haven't necessarily been consciously aware of this situation for the past three years.
Anyway, the other night, my battery broke. I don't know how it happened. I was running on battery power and walked away from the computer. The battery ran down to zero and the computer shut itself down. That's happened before. But when I plugged it in to recharge it, the battery started giving me error codes. I think it's dead. And I can't use my other battery, because it's one of the exploding ones. So I finally ordered the replacement today. It'll be here in 20 business days. I guess the real lesson here is, if there's a worldwide recall for your laptop battery, order the replacement right away. Because your other battery might break like three years later.