"Of course, when a chemically aged battery is replaced with a new one, iPhone performance returns to normal when operated in standard conditions." I find this

"Of course, when a chemically aged battery is replaced with a new one, iPhone performance returns to normal when operated in standard conditions." I find this disturbingly vague. If the slowdown was strictly due to physical battery degradation (and I haven't heard what specific metric(s) they use to objectively measure age/wear), then replacement should instantly reset performance rationing back to its starting point. They only say it "returns to normal when operated in standard conditions" without defining "standard conditions" and without saying how long it takes before they deign to allow you the performance you paid for. Their official Battery & Power page[1] acknowledges none of this beyond a separate issue affecting only a two-month manufacturing window of September-October 2015. [1] https://support.apple.com/iphone/repair/battery-power https://support.apple.com/iphone/repair/battery-power And weren't there earlier iPhone models that weren't designed with user-replaceable batteries?