One of the things that I'm always careful to measure when testing a new smartphone is the battery life. Being stranded with a flat battery or having to carry a external battery charger just won't fly and getting from one morning through to the follow evening is the minimum acceptable run time for me.
So when people tell me they don't get the same battery life out of their phone as I do, I always ask the same question - do you use Facebook?
Facebook is a resource hog on every mobile platform and in my view it is the main reason why others don't see the battery runtimes I get.
I don't install Facebook's app on my smartphones. On Android phones where it comes pre-installed I disable it. If I need to use Facebook I'll use the mobile site which is, fortunately, very good. Android users can even enable notifications from the mobile website in Chrome, if Facebook is an important part of your social life.
For iPhone users battery life gains are the biggest benefit of ditching Facebook's app, but if you're using an Android phone you'll find that there are performance gains too. Facebook eats RAM and, without the control iOS exercises on background apps, that can make your phone feel sluggish.
So drop the Facebook app and win back more of your smartphone.