I used to have two batteries for my first phone, a Nokia 5110. It was a hand-me-down from my mum. I don't know why we even had two batteries for it since the batteries used to last forever.

At some point, the industry became obsessed with making phones as thin as possible, removing standard things like removable batteries and the 3.5mm audio jack in the process. I wouldn't mind if my phone was a big thicker in exchange for those features. :(