My iPhone has a lithium battery, and our engineer Matt noticed that I had very little charge left on it - somewhere around 7%.  He said "you are going to send your phone to an early grave like that"....

He explained to me that the "old" style of battery, the nickel-cadmium (Ni-Cad) battery, was the battery that you were supposed to charge fully, and then allow to discharge fully before recharging, fully, of course.  This article from Gizmodo explains the ins-and-outs of charging your battery in a manner that will ensure a full life.  Battery life, that is....

 

(Via Gizmodo)