I could be wrong, but the cycle count, although easy to do, is not the whole story. There is a ton of hard evidence that lithium batteries degrade faster when charged above 80%, or depleted less than 20%. Thus deplete to zero and charge to 100% will result in an accurate cycle predicted lifespan repeatedly, but not an optimal long life.
My hybrid (which has a lithium battery) automatically keeps battery charge within a very tight range close to 50%. Some BEVs like Teslas warn you like crazy when you get too low, and go into a limp mode or even turn off to prevent damage, and limit regular charging to 80% (which can be overridden should you need more range on that day).
Cellphones users tend towards worst case charging to 100% overnight, and often depleting to very low levels. I recently bought an iPhone Mini and find that 30 minutes of timed charging a day keeps me between 85% and 30% with some ease. So for the first time in my life, I'm not leaving my cellphone plugged in overnight.
The APMs unfortunately have a cellphone like use case. Very difficult to manage charging levels, even with 20 hours play time. Unless Apple has built in some algorithm similar to hybrids to have top and bottom capacity margins for long life, I fear regular users may suffer from 3 years or less battery life before needing for practical reasons to replace it.
In fact, the same may be true for irregular users like me. While I have now returned them (today), I did have the battery go dead on me once with a couple days of disuse (never used the case). That also doesn't bode well for battery life.
