Re: how often do you charge your battery
I charge my 6+ every night. It doesn't make any sense to let the battery going completely down and wait until I charge it again. I don't know what will happen the next day, so it's good to have the phone fully charged instead of taking a charger and a cable with me.
Maybe a spontaneous trip somewhere with friends and you need some maps, take a lot of pictures and videos, need a flashlight etc. So just charge it and you don't have to think about battery problems
I'm using an iPhone 6+, which has a really amazing battery, still I want to be one the safe side