With my iphone, i wake up, walk to work and listen to music, get to work, and for the next twelve hours id listen to music, text and send off emails. I would have to have my phone on the stereo dock to charge for most of the day if i wanted some battery to have music on the way home from work. With my One, i do the exact same thing, without the need to charge all day long, and when i get home i still have between 10 and 40 percent battery life depending on my usage for the day, and then i fall asleep and let the phone charge while i sleep. I cannot attest to how much longer it takes, but i can tell you that my phone lasts long enough during the day that when it does come to charging it, i personally dont know a difference, although i know one does exist.