Scientists say your cognitive resources are limited, so use them wisely.
If you spend time at the beginning of the workday trying to decide whether you should empty your inbox, grab a cup of coffee, or attack that project proposal, you'll have less mental energy left to sit down and work on that project proposal later.
Sticking to a routine lets your brain run on automatic for a while, so that you barely use any mental energy.
As Charles Duhigg, author of "The Power of Habit," told The Chicago Tribune: "Routine basically gives us the mental freedom to think about what's actually important. That way we don't have to think about all the mundane aspects of life."