In a groundbreaking article T. L. Freeman discusses the relationship between actual age and effective age. His conclusion is that the passing of the years goes faster as we grow older. This makes sense; for instance when you are 10 years of age, a year represents 10% of your life, and seems like a very long time. However, when you are 50 years old, one year has reduced to only 2% of your life, and hence seems only one-fifth as long.Summarizing this work, Freeman comes to the conclusion that the actual age (AA) needs to be corrected for the apparent length of a year (AY). The apparent length of a year is inversely proportional to one person's actual age
via everything2.com
Enjoy yourself now kids because the break even point is about 18 years of age!