Seems to run as long as my standard OEM battery. It also charges correctly in the aftermarket docking cradle/charger offered by BarginCel (my OEM battery does not charge in it due to a slight size difference). Two of these, along with an aftermarket charger, makes a pretty good solution for those running out of juice all the time like I had been doing (and a lot cheaper than buying the new 1500MA Slim Extended from Expansys for $50!).Couple of tips:1) Use the OEM A/C charger whenever possible to charge a battery in the phone... it charges about twice as fast as using a USB cable to charge-up. I have two: one for the office, one for home.2) Make a habit of charging up your batteries at the office (if possible), where you probably have the time and desktop space to do so easier than at home.3) If you are really going through batteries, buy two of these, and consider buying the bundle with the sync cradle with spare charging slot. If you are only going though 1.5 batteries a day (devils advocate here), consider buying the new 1500MA slim battery from Expansys, since it's equal to 1.5 batteries, lets you keep your existing holster/skin accessories, and in the long run, might be worth the extra $40 over the price of this battery IN SAVED TIME AND HASSLE!Just my 2cents!