Earlier quoted context omitted.
Another thing you can do: scroll through your app list and delete all the ones you don't use. And if you keep your phone in flight mode when you're not using it, you'll quadruple your battery life or more. Both because the radio is off, and also because apps aren't waking up the CPU to spy on you every few minutes, since they can't transmit it.
Quadruple? Depends on how you're counting I suppose. The problem with using flight mode is that the phone then becomes useless at its job as a phone, i.e. a device that other people can use to call you.
Highly depends on signal strength, too. Having a phone with only one bar of LTE absolutely murders battery life, so that claim is probably accurate in that circumstance.