Honestly... Do you drain your battery on a regular basis? If you do, the mophie is a great purchase. In the summer I do a lot of long distance biking, and I have to leave my phone on to track my ride. So the mophie is a must. However in the winter, I find that I don't use it as much as I normally would. I usually just leave it in my jacket pocket and if I ever need it I know it's there.