A 2010 Time Magazine article about the plateau effect—Americans not seeing significant rises in happiness levels as income rises above $75,000—inspired my first intensive study on the relationship between money and happiness. Though roughly 15 years have passed, and more nuanced conclusions have been analyzed, the eye-opening revelation remains an essential reminder for retirees. Namely, happiness isn’t only about the money itself. What people do with that money can often be the difference between a happy and unhappy retirement.