It's good to give work as hard as you can.
Greg works on Amazon's Mechanical Turk on the side to help his retirement account.
Greg wants to save money.
Greg works for four hours a day, six days a week, and earns $300 a week to put into his retirement account.
Greg works for an hour a day, two days a week, and earns around $40 a week to put into his retirement account.
Greg's retirement account grows, and he has enough to live on at retirement.
Greg's retirement account hardly grows, and he has very little when he retires.