I must say that I'm really disappointed with my Z10's performance on 10.2.1. Some owners are saying that it got better for them after 4-5 days, but I'm not really seeing any improvement. Here's my typical day. Phone gets taken off the charger at 7 am. From that time until 5, it'll get used for ~30 min. of playing games, ~ 45 min. of talking, and ~1 hr. of e-mail/messaging/facebook. The battery shouldn't be dropping even to 50%, but mine's at ~33%. I honestly don't remember the last time I've had such a crappy performance from a phone's battery. And it's not like I don't know how to manage my devices. There are almost no Active Frames open. LTE is disabled. NFC is disabled. I'm connected to WiFi more often than not. The only thing I have on constantly is Bluetooth (as I do on all of my other phones). I tried using my Pebble with the Z10 but abandoned that, as that seems to demolish my battery even faster. So, I thought I'd see how other Z10 owners are faring. But, if any Q5/10 or Z30 owners would like to chime in, I'd love to hear it.