I&#x27;m not sure what the cutoff should be, but at least a week.  My smartphone uses less than 10% battery a day on standby.  My last smartphone wasn&#x27;t that different.  And this isn&#x27;t even in a spot with a good signal.<p>On the other hand if I let skype run on the data connection, it uses hundreds of megabytes of mystery data and burns out the battery in two days.