Some people use “to-do” lists all the time. Now the research tells us why they help.

An article by John Tierney in the New York Times Magazine, http://www.nytimes.com/2011/08/21/magazine/do-you-suffer-from-decision-fatigue.html?_r=1&hpw, explains how “decision fatigue” hampers our ability to evaluate options and arrive at sound decisions and choices. The mere act of having to evaluate options wears down our capacity to think clearly about which option to choose. After a while, the mechanism gets tired. We tend to think less carefully and decide more conservatively.

The article gives example after example of individuals who are more successful at making the right decisions when they are well rested and well fed. It cites experiments where a bit of food, such as snacks, improves decision-making by replenishing the energy used up in earlier decisions and choices. Even an activity as simple as shopping in a supermarket can deplete our decision-making capability as we have to pick one type of food to buy over another time and time again.

To-do lists work because they make decisions ahead of time. Later on, when you’re tired, you don’t have to go through the effort to evaluate which action to take because you can simply do what’s on the list. The article talks about the challenge of maintaining willpower over time and the greater difficulty, for example, that poor people have in making ordinary purchase decisions because of the trade-offs they must evaluate that richer people don’t.

Most of us have heard the aphorism, “Plans aren’t important but planning is essential.” Now we know why. Planning organizes what we care about into the future. It commits us to our priorities now, and saves us the burden of having to make a decision later on, when we may be in poorer condition to do so.

Will this help you? Start each day with a to-do list for a few weeks and find out.