Dating myself here but, DOTA.

Yes. I just replaced the ones in my wife’s Sony earphones by following a step by step guide on ifixit. Cost me $15 for the batteries including shipping, and they’re not even any sort of exotic type or size.

Edit: okay just read the article. Guess these are a lot more convenient to replace than the Sony ones.

Do what makes you happy, my dude/dudette. And good luck with the clinic visit!