To-do lists are one of productivity's oldest and simplest tools. Yet most people don't use them correctly. This isn't fully their fault. At least part of the blame goes to today's to-do list apps. They push you to prioritize tasks in an overly simplistic way.

Most to-do lists make it easiest to prioritize tasks by due date and so most people organize this way. When entering a task, the due date field is very explicit and accessible. Many of the apps also include by default deadline-based folders like "Today" and "Next seven days" and make calendar views available. They are built around due dates.

Yet you shouldn't be prioritizing your tasks based on due dates alone for these reasons:

  • Most due dates represent changeable or arbitrary deadlines that don't really need to be met, making it difficult to pick a due date and highly likely the due date you set will be wrong. Research on one to-do list app found that people change due dates on over half of tasks.
  • Priority level is a factor of more than just due date. For example, a 30-minute task due in two days is lower priority than a two-day task due in three days despite having an earlier due date.
  • Due date-based prioritization pushes us to complete many small, mundane tasks, crowding out time to complete high-impact activities.

This isn't some esoteric debate for time management aficionados. A due dates-based approach causes real problems. When coaching professionals, I frequently find that people are missing deadlines and squeezing out time to do important work because of this limited understanding of prioritization. Some wait too long to start work, not realizing getting input from their supervisor will take time. Others rush to get work done, pushing off other more important work, only to realize that their supervisor won't even look at their work for another week.

Instead of anchoring tasks to due dates and managing to deadlines, assign them a relative priority level (e.g., high, medium, low, none) using the following factors in addition to due date:

Firmness of the due date.

Some due dates need to be hit or there are real consequences (these are hard deadlines), while others are more like suggestions. You can tell whether a supervisor or client-imposed due date is hard or soft by gauging the level of uncertainty, ambiguity, and apathy in their communications about the due date. Soft due dates have more of these three.

Task duration.

This should go without saying, but longer tasks are higher priority than shorter ones, all else equal. If you're generally not sure how long your work takes, there is an approach to managing your calendar that should change that. If you're not sure of a specific, larger task's duration, take 15-20 minutes to explore the task so you can make a reasonable estimate.

Uncertainty around task duration.

When you're unsure how long a task will really take, make it higher priority to protect yourself against the unexpected.

Number of other people the task depends on.

The more dependencies a task has, the higher priority it is. You have less or no control over when dependent tasks get done, so you want to do your part and then, get them to others as quickly as possible.

Task importance. 

In a perfect world, you'd beat all deadlines, making task importance less relevant to priority level. Since no one hits every deadline, prioritizing important work increases the odds you'll hit your deadlines for high-priority tasks.

You probably aren't surprised by any of these, yet if you're like most people, you assign due dates, not priority levels, to your tasks and keep your list sorted by due date or use the default calendar-based views. Embracing this more nuanced view of prioritization requires you to go against most apps' design and do a quick mental calculation of tasks' priority level factoring in the characteristics above when adding them to your list.

Making this decision should only take a few seconds because you only have four choices rather than the literally infinite number of possible due dates. Keep your list sorted by priority level and look to your high priority items first when planning out your days.

By doing this, you can resist the push to oversimplify your task management system and increase the success in accomplishing your priorities.