iPhone the 2-year-old has an integrated haptic feedback system, or haptic response, practically generating vibrations when something happens on the screen, whether we're talking about using 3D Touch, deactivating some functions, performing a refresh, or many others.
Apple implemented this system for the iPhone together with 3D Touch, it uses a vibrating motor to generate localized vibrations in various regions of the screen, and this consumes much more battery energy than you might imagine and I recommend you to disable the function.
On the iPhone 7 Plus, I realized that this haptic response function reduces the battery autonomy by up to 1 hour, so I lost an entire hour of use, or many hours of stand-by, just to feel unnecessary vibrations on the screen when I press the buttons like to deactivate functions, delete emails, etc.
For me this feature is completely useless, but I think there are many among you who would be happy to increase their battery life quite a bit by disabling this haptic response system of the iPhone and if this is true, then you can get away with a few seconds by him.
iPhone 7 and iPhone 8 all have this feature enabled natively, but you can disable it from Settings > Sounds and Haptic Feedback Haptic Feedback, Configurations > General > Sounds and Haptic Feedback > System haptic feedback whenever you wish.