Erratic battery issues seem to be the plague of WP. Right from the beginning. And in the forums there is a whole lot of well intentioned observations and advice from individuals that, really, know nothing about technologies. Not just the battery, but the phone. I've a half century dealing with electronics and battery technologies.
My battery experience on my Nokia 810 might be politely called "variable." BTW, the only way to really get a handle on what is going on in your phone is with a good battery reporting app. I use and like Battery Sense. You also have to use a stable data base, and that is in standby. My phone seems to use battery at the least in the hours after recharging. Typically, 1% or less per hour. But my experience shows that anything up to about 5%/hr is routine. OTOH, weird sudden discharge rates of 10-25% per hour! Usually rebooting fixes that.
The battery issues have been addressed to some degree of success with OS updates. They have nothing to do with Amber, Black, or Cyan. There was an update to 8.1 mid June which really helped.
I have the following always on: Wifi, 4G (it uses more power than 2G), Glance, and Cortana. People have reported that having email updating automatically, and the FB app are stealth battery suckers. Oh, I run 8.1 Update via Preview for Developers.
Unless something is really wrong in your phone or your battery is defective, a careful analyis of these matters will likely fix your issues. You can also get replacement batteries of higher capacity for most phones, even the "non-replacable" types. The 2500mah hour version I bought to replace my standard 1800mah definitely, absolutely has a lot more capacity than the OEM and has performed well for almost a year.