Basically, iOS 7 killed my battery life. It seems to be going around; I have the very iPhone 5 on Verizon that Ars Technica famously reported to be pummelled by the upgrade. They have since run the test with an AT&T phone and with all cellular connectivity disabled on the VZW phone and found some slight improvement, but nothing great.
Well, today I took the phone to the nearest Apple store and two young ladies gave it the full rundown, checking the logs and running diagnostics. They found that among other things, the battery is very near the borderline of requiring replacement after only 10 months; in fact they intimated very strongly that a battery replacement would be inevitable before long and would be covered irrespective of warranty status. They also found no less than thirteen processes with fairly regular crash issues since Sept 21 when I restored the phone from scratch, of which fully have were system processes rather than apps in user space.
So for the time being, they wiped the phone completely and set it up brand new with iOS 7.0.2, and I manually filled in the account info and re-downloaded apps. No sync with a desktop, no restore from backup. This is clean and pristine as I can make it. If the problem persists after a couple of weeks, and the logs don't show any more crashing issues, it probably means a battery replacement. But if the logs show the kinds of continuous crashing we saw today...
I don't know. If I had to guess, right now, I would say there's something squinky in the specific build of iOS 7 for the iPhone 5, model A1429 (the CDMA-enabled one), and that the impact on battery is made worse by the fact that Verizon never seems to have more than 3 bars of LTE service anywhere (and thus pulls harder on the battery). And that the physical battery itself in my particular phone has been taxed something fierce (which this year at work strongly supports).
But if the phone still dies on the regular after all this, I think it may be time to give some serious consideration to getting off VZW and going back to a GSM carrier where the fallback from LTE is something at least potentially faster than 2.4 megabit downstream.