I went the other route, which when I owned the Thunderbolt I posted that I thought having a spare battery was going to be a chore, but I stuff the spare battery inside the Beats carrying case and it give me an excuse to carry around the earphones for the phone. One benefit for me having the spare battery, typically when I'm in need of the extra battery it's because I'm using the phone excessively. Having to pop out the case to swap batteries gives me an excuse to let the phone cool off (it cools off much better with the back case off, and the battery disconnected). With the external charger I'm not overheating the battery/phone by charging and using it at the same time.