Contrived hypothetical: It's tuesday evening, and I'm updating my to-do's before tomorrow. I have 3 hours after work, and 3 tasks: 1) A meeting (Important Urge

Contrived hypothetical: It's tuesday evening, and I'm updating my to-do's before tomorrow. I have 3 hours after work, and 3 tasks: 1) A meeting (Important Urgent) 1 or 2 hours 2) Buy a gift for someone's birthday (Important - can be done any time but must be done) 1 hour 3) Check the marketplace for a limited sale (Urgent - much better if done immediately, but doesn't matter so much if not done) 1 hour If task 1 takes only one hour, I do 3 then 2. If it takes two hours, I do 2. There's two contexts above. Obviously as you pointed out, once you actually get to doing a task, there's only one context. But the point is that when adding a task to your to-do list you don't yet necessarily know what that future context will be. Your choices here are to either make a priority queue for every possible future context (reasonable for this simple case, but doesn't scale to a more complex one), or mark tasks with the relevant information that will let you easily assemble the appropriate priority queue on the fly, once the context becomes clear.