Proper way to charge your not 4 battery.

Read Battery University - How to Prolong Lithium-based Batteries. If you study the chart (second figure, the first is a graph), you'll see that you'll get the longest life from a lithium battery by charging it at the 50% point. (Charging at anywhere from 40% to 55% won't change the lifetime much.)

Letting it run down to 5% regularly? Buy stock in a battery company. It may last a little more than 6 months, but I wouldn't count on it.

If you need more capacity than 50% between charges gives you, buy a second battery and swap them when the one in the phone drops to about 45%. Two Anker batteries (they're good) and a charger to charge both at once (one in the phone, one out) will cost you $25.

I'll keep on running mine down to 5-10%. Been doing that for years and have never had to replace a battery. My iPhone 5S is over a year old now and it still lasts for nearly two days on one charge. My old iPhone 3GS still lasts for a full day. My two year old Nexus 4 still lasts for a day.

I see no reason not to let it get down to 5-10% before charging.
 
Sounds like you're a much heavier user than I am. I'm typically in an office all day and on wifi with good LTE signal so my standby battery drain is minimal and my usage is very light since I'm at my workstation for most of the time.

When you're charging twice a day what is your battery % at?

This.