I had a Genius Bar appointment this afternoon because my 10-month old iPhone will shut down almost anytime it gets below 30% battery level. One day it went from 76% remaining straight to 1% remaining, stayed at 1% for almost 6 hours (with use!) and then died. As soon as I plug it in the phone powers up and reads at least 22% battery. So obviously stuff is funky. Anyway, got the battery tested...the results are displayed on a square about 2" x 2", divided into 4 quadrants. If each square is a 1 x 1, my battery tested at about 1/8" (at most) above the red "defective/replace" quadrant. I was told I could have my phone swapped now for $79 or keep coming back until if fails, "which it will almost certainly do" according the guy helping me out. I have Apple Care I'm not limited to a 1 year warranty, but if the battery is about to fail and a replacement is all but certain to be necessary, why not just swap it now instead of leaving me with a device I cannot rely on and asking me to make multiple return trips until it fails?