- Sort by orders. If seller has sold the most, probably a reliable seller.
- Buy a handful (or samples) first (you can ask seller that you need samples first), and test their capacity (using e.g., a good charger, I have Zanflare C4). The model I mentioned should have 3Ah (or 3000Ah). If confirmed, those are legit cells.
Apple has had a web page about batteries and good maintenance practices [1] for several years now. But most people wouldn't know about it or read it unless they searched for it.
Cut with lasers or electron beams as far as I know, and the masks are bigger by some multiple. Also have really weird patterns, since they have to correct for how the light-waves interact due to the small size.
I wouldn't be surprised to see that it increases overall spending. For me it's like second nature. I don't even think about the cash back. It's more like, oh I'm eating out, need to use the 3% cash back for dining card.
While straight cash is not something i have heard of locally, i know that frequent flier points got a bad rap because it was found to be market distorting.
[1] https://www.adelaide.edu.au/degree-finder/2020/bengh_behe&es...