I plan every day. I talk about that a lot. Some people record what they accomplished at the end of the day. Me, I prefer to tell myself what needs to be done and then do it. I think about planning my time a lot like a financial budget. If I just spend money as my needs and impulses dictate, I'll run out of money for the things that matter.
The same holds true for our time. When I schedule my day ahead of time, I am setting a budget for one of my limited resources: time. Without that plan I will spend my time on less important things, and with much less effectiveness.
Where are you spending your time, and how could a budget help you get the most out of what you have?