I replaced my iPhone battery myself. Here's what happened

I thought I'd found a bargain when I discovered a pristine-looking iPhone 6 on eBay for only £75 (about $100 or AU$140). But that excitement quickly dwindled when I realized the battery had aged to the point where the software throttled its performance. But instead of casting off the phone and getting buyer's remorse, I decided to buy a replacement battery and tools from iFixit to have a go at replacing the battery myself.