What ^^^ (Tater) said. Turnoff Background App Refresh, and limit Location Services to apps while using, or not at all!
Ok...I'm still a little iPhone illiterate. How do I do that?
Overall the battery in my 6+ lasts MUCH longer than my HTC ever did.
Settings -> Privacy
You can choose the apps you want to leave on (I have it one for 3 and off for all the rest).
Echoing the other threads of discussion, my Sprint contract is up 11/1 and I'm going AT&T with a regular iPhone 6 (the 6S is too big for my taste and doesn't fit well into my pockets).
I've noticed that off-brand charging cords with the 5S seem to have brown spots on the contact points and if you flip the charging plug over it seems to help the phone charge...I sit in a concrete bunker at my office so mine is plugged in and charging all day long...plus I run bluetooth to a small speaker on my desk for podcast listening.