The to-do list is an under-appreciated productivity tool, but it's one that can make a world of difference in the way you handle your day-to-day tasks and even your future goals.

There are a number of benefits you experience when you keep a to-do list on hand, but I have found the four benefits below to be the most compelling.

To-Do Lists Hone Your Estimation Skills

To make an effective to-do list, you must do more than simply write down necessary tasks. It's also important to estimate how long each task will take you to complete (this helps you organize your days better) and determine which tasks are higher priority than others.

This skill has proven to be invaluable, both professionally and personally.

Professionally, it gave me insight into the prices I should be charging my clients because I was better able to determine how long different projects would take me. (I charge by project as opposed to hourly, so this is important to figure out.)

Personally, it allowed me to take an honest look at my non-work related goals and approximate the time and energy involved. This makes it easier for me to break my long-term goals into smaller chunks and have a better idea of the time it'll take to achieve each.

To-Do Lists Free Your Mind of Clutter

Have you ever been in the middle of one task only to have your mind elsewhere?

Before to-do lists, my thoughts were constantly interrupting me. I would scramble for a piece of paper, usually the back of an envelope or a coffee-stained post-it, and write down the task so I wouldn't forget. What would I do anyway? Forget. Because my to-dos were scattered throughout my house.

A master to-do list is a great place to “dump” all of the projects and tasks clogging your mind. If your boss hands you a new assignment or a new goal pops into your mind, you can just add it to your master list and then get back to your work.

To-Do Lists Help to Streamline Your Day

I have two to-do lists.

My master to-do list is a jumble of my professional and personal goals. It includes projects that I'd like to get to someday but that don't really have a deadline, and it also includes goals I'd like to accomplish in the next two, five, and 10 years.

My daily to-do list, on the other hand, is my daily navigator. On occasion, I'll take items directly from the master list and move them to the daily, but more likely I'll break the master tasks into smaller chunks and add those throughout the coming days.

Your master to-do list can be as long as you'd like, and how you organize it really doesn't matter. As long as you know what you're looking at, you're all set. Your daily to-do list, however, should be short. And while many successful people suggest a maximum of 3 items, I'm partial to the 1-3-5 rule introduced at TheMuse. This means your list will have a maximum of 9 items — 1 big, 3 medium, and 5 small.

To-Do Lists Give You a Sense of Accomplishment

At the end of the day, I know that if the bulk of my to-do list is crossed off, I've had a productive day.

In the era before to-do lists, I constantly felt unsatisfied with my work. I had no clear way of knowing whether I was doing enough, and I had no concrete way to see whether my daily actions were lending themselves towards my bigger goals.

There's nothing more satisfying than crossing off my tasks throughout the day.

If you use a to-do list, what benefits have you noticed? If you don't have a to-do list, what kind of tools do you use to keep organized and motivated? Let me know in the comments.