Hofstadter's Law addresses the common problem of accurately estimating the time it will take to complete a task.

 "It always takes longer than you expect, even when you take into account Hofstadter's Law."

Bill Gates' interpretation of this law especially resonates with me:

"Most people overestimate what they can do in one year and underestimate what they can do in ten years."

• You overestimate what you can achieve in a gym in one month, and underestimate progress for six.
• You overestimate your ability to learn something in a month, but underestimate what you can learn in one year.
• You overestimate your saving ability for a particular paycheck, but underestimate what you can save in one year.

While planning something, I try to take this law into account and be more humble in my short-term goals, and more ambitious with long-term ones.