OEM batteries might last longer

That is a longer life. Probably lasts longer on a charge too.

Most third party batteries swell up after a while.

I have two old batteries, neither have swollen up. One is for an E-PM2 or 1. They are compatible with the E-M10, and E-M10 Mark II.

Already said my sister could have the extra battery. It's old anyways.

Neither have been used that much, probably why they still work. Will third party batteries stop holding a charge and swell up if you don't use em much? Maybe once a year or something. Might last you ten years if you do that.

On another note, don't try to open a battery, you risk an explosion by doing so. Thermal runaway. If no explosion, probably a fire.

How long till my phone lights up? Probably when I'm talking on it. Burning the side of my face, having to get it removed. Fake skin installed.

How does Apple have so much extra money, if batteries are hard to make correctly? You'd think it would cost a fortune to design a battery. They could outsource it. They probably charge a fortune though. Unless it's a cheap place, that cuts corners, and likes fires and explosions.