Should you power down your iphone before charging in order to prolong battery life? I've just had to replace a second battery on my iPhone 6 in under a year. The batteries were most likely damaged due to overheating. I talked to the repair person about the best way to prevent this in the future. He gave me three suggestions:


Avoid charging your phone for more than 4 hours at a time (ie- don't charge over night).
Remove from the case before charging or whenever it gets hot.
Power down the phone before charging.


Based on many posts in this forum, #1 is incorrect #2 seems like quite a good idea. I might even purchase a different case that would give the phone better breathing room.

However, I am unsure about #3. Does powering down your iPhone before a charge help make the battery last? Does it do anything positive?
There is no need to turn off your iPhone.
I have asked Apple customer service the same question and they told me no need to do this at all. 
But you can use up iPhone battery to power off and then thoroughly charge it to 100% once a month. It is better for iPhone battery.