I don't recall anyone else ever mentioning this in the various 'battery-gate" threads which abound on MR. Before I received my new iPhone 4s I was still sporting my trusty old iPhone 3G, which I've now owned for exactly 2 years. About a year ago I became concerned that the battery would be toast before I was due for an upgrade. I did some research on replacement batteries as well as proper charging technique to maximize the life of the original. I was pleased to find that the Battery section of Apple.com recommended the exact regimen I had been employing previously: ALWAYS be sure to wait until your phone indicates 20% or less 'juice' remaining before you begin another charge cycle. While the above advice is not verbatim, I am 100% certain that this WAS the official stance of Apple, per it's own website less than a year ago! NOW I see Apple has done a complete 180 degree turn and suggests that the Lithium Polymer batteries in iPhones suffer no ill effects from chronic charging before the 20% remaining level. There is an illustrated explanation of how/ why this is so on the Apple.com so I will spare you my attempt to paraphrase. Has the composition of iPhone batteries changed in the last year? I find it unlikely. What else would explain this drastic change of advice from the manufacturer? Note: My 3G battery held up better than I projected and is still quite usable. I received my 4s the day after launch and strictly follow the OLD advice from Apple. No problems with battery life whatsoever.