Let's talk about iPhone battery health.
More specifically, that number that you can see if you head over to Settings > Battery > Battery Health.
If your iPhone is new, then you expect this figure to be at 100%.
And you probably expect this number to tick down as your iPhone -- and the battery it contains -- gets older.
But what if I told you that number was meaningless?
What if I went further and said that there's nothing that you can do to keep your battery at 100% ? That, in fact, how long it takes to tick down from 100% to 99% is based on chance?
It all starts with the fact that the rated capacity of the battery is an estimate.
Not all batteries are the same.
Some batteries have a little more capacity when new. Others a little less.
YouTube channel Payette Forward took a deep dive into the numbers, and prove that the Battery Health number far from a perfect science, and that trying to keep your battery at 100% is down to pure luck.
Bottom line, each time you charge up your iPhone -- or anything else containing a battery -- the battery is wearing out a little bit.
Batteries are a consumable item. Keep hold of your device for long enough and one day you'll need to replace the battery.
Why has Apple included this figure in iOS?
Maybe it's there as a visual reminder that your iPhone is getting old and you need to replace it.