But considering the fact that I've been on the HTC One M7 for about 2yrs now, maybe a bit less? With the way I use my smartphone, the battery tends to not last me more then 10hours in a day.
I do everything you can think of with my phone, music, txt, data transfer, games, emails, some compiling in a terminal window and what not. Of course, I'm a power user, I wouldn't be anything else.
So the objective was to use my phone like I normally do and when I'm running low on juice, just snap this on and charge the phone back up.
This has brought me to a point where now I'm able to use my device for nearly 32 hrs without having to physically find a power outlet. But I also carry a battery pack as well so technically could be a few days without an actual outlet.
What is the end results of this? Well I almost had about 8hrs of screen time for nearly 32hrs of usage in general. I'd invest in an other battery case for my next phone anytime. That extra edge is nice to have.