This is really simple. If your phone isn't heating up while its draining fast, it's just normal battery usage and battery calculation learning. If you're getting a really warm/hot back of the phone then you know it's happening. I agree that easily most of these people are just not waiting for the battery to settle in after a few days or they have an insane amount of things going on/never stop using their phone and they need to set realistic expectations for themselves on smartphone use. You can't just game/watch videos/talk for hours all day plus do all the other usual things and have stellar battery life. I can say this because I've had the battery mysteriously drain quickly several times sometimes as often as once a day, BUT I've also had stellar battery life which is actually the norm. And I don't change anything I just use and enjoy the phone. There IS an issue, but it's nowhere near the scale it appears to be with these forum posts. No you absolutely should not have to turn off things you genuinely want to use, however you should recognize that depending on your habits, whether or not it's going to be a heavy day of usage, and the signal strength where you are, you may need to adjust accordingly. I usually like to leave WiFi and BT on all day out of convenience, however I do disable them when I know I'm going to have a heavy day in a low-signal datacenter. Yes I've had days like this:
(11PM after charging mid-day)
But usually I have days like this:
(1:28AM after a very long day without charging)
I've now had my Lumia for around ten days and it's absolutely gotten better battery life overall now, because the calculations have settled down a bit. Don't freak out day one (or even day three), you have to give it some time before you can properly judge. I always have GPS on as well, though not in all areas (not in People Hub, not on camera), I have an exchange account always syncing, and I have FIVE other e-mail accounts that sync once an hour. Some hotmail some google. I also check my twitter feed religiously. The 920 battery is great UNLESS you hit the occasional mystery battery bug and also ONCE you have let it settle in after a few days.
Yes occasionally someone will get a bad battery, but do you guys seriously think every other post where they returned the device within a day or two or some guys are on their third one are actually that many legit battery failures? That's insane and I absolutely don't believe that.