Steve's been thinking about battery life and discusses how long your smartphone really needs to last to be useful. As long as you can get through a working day, any excess battery life is a bonus. All your phone needs to do is "cross that battery threshold"...

In essence, the power to get through a hard day's work marks out a 'battery threshold', if you will. Less than a certain battery capacity (relative to overall functions) and the result will be misery. Greater than the same figure results in happiness and contentment.