From “Love Your Neighbor: How Psychology Can Enliven Faith and Transform Community” by Katherine M. Douglas and Brittany M. Tausen
Researchers have found people always assume they will be able to do more in the future than they can actually do, because they underestimate how long things will take. This is called the planning fallacy. Disappointingly, simply knowing about the fallacy does not help people to avoid it. We remain woefully optimistic that we will be able to accomplish more in less time in the future.
The cost of this fallacy is high. Our schedules are packed to the brim with no room to just be, let alone notice the needs of those around us. A more reliable approach to counter the planning fallacy is to intentionally overestimate how long things will take you. For example, if you believe that it will only take you fifteen minutes to run to the grocery store, you can set aside thirty minutes in your schedule for the task. The more complex the task, the more you should overestimate.