"Out of sight, out of mind." The reverse of that is true too. When it's in sight, it's in mind and we cannot help but be distracted.
Studies have shown that a person working with a messy desk will spend, on average, one and a half hours per day either being distracted by things in their view or looking for things. That's seven and a half hours per week.
Keep the clutter before you at a minimum and you will have a more accurate focus on what you need to do to increase your daily productivity.