You do a lot of work in your life. From age 4 or 5 to 17 or 18, you are in school. If you choose to go to college 18-20 or 22 or even beyond, and then you need a job to provide you for the rest of your life until retirement. You'll be between 55 and 65 by then. So from age 0-4 and 65 until you die, you're just working.