Does it hurt the phone's battery to charge it before it is totally dead?

This is a heavily debated issue, not only with iPhone batteries, but also with batteries for almost any other electronic device. Some think it is paramount to wait until it is almost drained (10%>) before charging it, while others don't think it hurts it at all to charge it whenever you like. The only thing I would recommend you don't do too much is let it drain to 0% and let it sit in that state for too long. You may also want to be more careful with when you charge it the first few times you do (this is known as conditioning the battery).

Hope that clears it up a bit for you.

-bb

http://www.apple.com/batteries/

No, it won't hurt it. In fact, it's not good for a lithium ion battery to drain it absolutely to dead.

Apparently not, I do it all the time with several iOS devices daily.

Here you go 🙂

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries