Connect and plug in the power adapter and then hook up the optical cable, and it's pretty much ready to go -- save for some pairing woes that required us to unplug everything.
For comparison's sake, the Jawbone up is rated for up to 10 days but then again, you have to plug it in every time you want to sync, and the cap covering the charging piece is easy to lose.
If we get plug-in hybrid cars, you can plug it in at night and sell back electricity to the utility, and then charge up your car again in the morning before you leave.