I decided I’m still not ready to spring for a new iPhone 8 or iPhone X. So I went to the Apple store here in Seattle, to inquire about a replacement battery for my old iPhone 6s. (Apple has a special offer of $29 for battery replacements for certain older phones. Normally they charge $79).
Well – it turned out that I’m going to get the battery for free. The analysis they ran at the store showed that the battery in my phone has gone through 533 charging cycles, and its capacity is now down to 80%. It is also from a batch of batteries that had since been marked as slightly flawed – hence its free replacement.