I suspect my iPhone's battery is now much worse than it used to be. How can I assess this? Is there some kind of test I can make, to compare it with Industry average?
How long can I reproduce a movie, a specific app, or something like that?
There are apps that you can use to assess battery health, but I recommend a Mac/PC app called iBackupBot. Tether your device to your computer, navigate to the lower left window pane, select the device, and click the link for
EDIT: The best iOS app I have used to provide this info is BatteryLogger Plus. However, it requires a jailbreak. Non-JB apps seem to provide optimal operating information, but not cycle count information. This may be a function of App Store limitations, which is why BatteryLogger Plus is a Cydia store app instead.