It can never be said enough - that a bad plan that is well executed will succeed, and a good plan that is not well executed will fail.  Without an execution plan for every part of your business' day to day operations, you can become a rudderless ship going in circles, never quite achieving your desired results.  Day to day demands will take you off focus.  It's just way too easy to get distracted and so much easier to stay focused with a clear plan.