In the last couple of months I have had to recharge my iPhone twice a day in order to make it through the day and barely make it through 6 hours of actual usage and no more than 8 with standby while in Wi-Fi. It's been happening to me since before updating to iOS 10 and I haven't seen any regression since updating to it. I know that batteries get worn from use and after one year since getting my 6s I feel like it's too soon to see this dip in battery life. Coconut battery also seems to confirm my suspicion since it reports that with less than 400 garage cycles my battery capacity is at 76% from it's designed capacity and I have been monitoring it since I got my phone last year. When the iPhone was new I was easily hitting around 8 hours of actual use and 16 in standby and my usage pattern hasn't changed since then. Spoke with AppleCare and they couldn't find anything wrong from their diagnostics but I'm not convinced. Am I right unsuspecting I have a defective battery?