What running applications and services are safe to turn off? Possible Duplicate:
  Knowing which applications to stop  




I just got a used Nexus One and I see a lot of running services and applications.  I'm wondering what negative impact there would be if I just started switching them off?  

For example, obviously, I don't want to mess with "Calendar," but what about "Calendar Storage?" If I install Handcent SMS, do I still need the Messaging-related services/applications?  Same for Media: if I install Winamp, do I still need those?
Calendar depends on Calendar Storage; Handcent still relies on the device's services for receiving messages; and I would guess that even if Winamp doesn't rely on Media, your wallpaper or notification sounds or something else does.

I would mostly leave these "System" services alone.  If you have battery trouble, it's likely due to user-installed apps.