Lithium Ion batteries do not generally like to go below their nominal voltage.
Originally Posted by falconrap
You're assuming that 0% means going below nominal voltage of the battery. This is not the case. The power management system in these devices is very good. They will monitor the battery and act accordingly.
Numerous phones I have tried, When they turned off at 0%, their battery voltage was still at or above NOMINAL voltage, never below. It's OK to go to zero percent if you chose to do so here and there and then fully charge, nothing wrong with that.
Like I said, as long as you're not going below nominal voltage, and you're not, so you should be fine.