i had been doubting my iPhone 5's battery for a while; so here is what i did. I kept 2 phones with me. iP5 : about 4 months old iP4 : about 2.5 years old. They are the excat copy in terms of apps, running apps, mail fetch cycle, etc. I anyways had 2 cellular connection and both were from same operator with same specs like download and 3G and those sorta stuff. From my end, i tired using the same apps on both phones at the same time for nearly 3 days and to my surprise, iP4's batter is better than iP5 on all 3 days, but a good margin, about 15 % of it. I am currently in India, and its not easy to just walk down to service center and they'll replace the phone..for them, battery concerns are not really defects, they are more user oriented stuff and they don't entertain a lot. so what can be my options..i am not very pleased that my 2.5 year old phone is outlasting my 4 month old phone so very consistently. for past 3 days, i didn't use any camera or messaging at all.