Planned work is defined. Unplanned is not defined so you need to Collect and Process it in order to compare with Planned work priority. You can define on the fly or schdule time for Defining daily. Anyway there's no sence in doing Unplanned work if it is not Defined and compared to Planned work. So use 2 minute rule to Define the Unplanned work as it comes: What's the outcome, What's the next action; and organize using 3D: Delegate, Deffer, Do.