Genius Bar FTW
Have a 22 month old 6+. The battery has been getting old. Enough that I have been using the phone way less than I would like.
Today it got really hot and would not charge.
The genius did a diagnostic and it showed some software crashes and charging to 92%. By those diagnostics he could have turned me away. But when we looked at the charging graph for today he could see what I was describing for not charging or lasting as you would want. He also took my word that I did all of the normal settings changes and resets etc one can do.
He gave me a brand new phone. It took a couple of minutes and bada bang I was out of there. Happy with Apple as usual. Not many companies allow their employees to really help a customer like that.
Be nice to these people. This genius made it happen. And get AppleCare+.