I've had a Centro, through Sprint, for about 2 weeks now. I noticed my battery would run down in a matter of hours, and I mean several hours.
Under the main menu go to "On Demand", Settings, Auto updates, set to NO.
Main Menu, Prefs, Power, Brightness, set as low as you like, turn the "beam" off also.
Remember, bluetooth transmits radio contantly, turn if off when not in use.
I can run on standby now for several days. Of course if I use it for more that two to three hours I have to recharge.
Sprint Mobile Email will work but won't notify you correctly if you enter your full email address. Use only your user name, NOT "
name@yahoo.com", correct example: "first.last" as username.
The only gripe I have is that I can't change the "vibe" I get when notified on Mobile Email, there appears to be no way to change it to an audible alert.
Other than that this is one great little phone!