Back when I purchased this it was doing an admirable job of charging my MP3 player and GPS. Times quickly change. Now everything is integrated into my phone and my phone is ONLY charged via USB.  In terms of longevity, this thing has paid for itself. When I'm on a plane, the extra power is generally used to keep charge at 100% while I enjoy an hour of casual gaming. Plane lands. Phone is still charged. Bonus: the A/C adapter is compact and useful by itself when paired with a USB cable.