Recently I've been looking a lot of posts here about many people saying that you should not let your battery discharge under 40%.
My best guess is to take care of your battery is not let to charge it 100% and not let if fell down 40%.
Well designed and built lithium ion batteries are lively enough that you should not worry too much. It is true that it is best not to drainage them to empty or near empty, or to overcharge them.
So I'd tend to say only use as much of the battery as you require when you need it, and charge it when you can, and you'll be fine.
I use my phone until it sticks to 15%,then hacks it into the outside battery or charger.
No issue where the battery records at night, it starts to plugg into the charger. I agree ! the heat is the main abjection factor.