So I've a question which I've always been wondering, ever since I started buying laptops a while ago. We all know that a battery will wear down after a while or two, especially if we have to use the AC power adapter, and eventually it'll get so bad-like mine-that your laptop won't be able to work off the battery at all, which sort of makes having a laptop pointless. Now, you'll see on Amazon or eBay people selling discount batteries that are cross platform, meaning that they can be used on a wide variety of laptops. Are these actually worth the money, or is it a false economy?