[ericabiz]

The 2013-2016 era Retina batteries are replaceable from independent repair shops (i.e. not affiliated with Apple.)

The batteries are glued in, but independent repair folks found a way to remove them with some isopropyl alcohol and old credit cards/gift cards or sturdy playing cards.

This isn’t for the faint of heart, as they can explode, but repair shops have experience replacing them.

[paulsmal]

Would be awesome if I can find some decent repair shop that can make it like new but unfortunately I had a bad experience with my previous macbook pro 2011. It was battery first, than some power controller. As they said apple stops making repair parts after few years and you can find change only in used laptops.

[spython]

It is quite easy to replace the glued in battery yourself, just with some floss and enough patience.