HOW much money do you need to be happy? Think about it. What’s your number?

Many of us aren’t satisfied with how much we have now. That’s why we’re constantly angling for a raise at work, befriending aged relatives and springing, despite long odds, for lottery scratch tickets.

Is it crazy to question how much money you need to be happy? The notion that money can’t buy happiness has been around a long time — even before yoga came into vogue. But it turns out there is a measurable connection between income and happiness; not surprisingly, people with a comfortable living standard are happier than people living in poverty.

The catch is that additional income doesn’t buy us any additional happiness on a typical day once we reach that comfortable standard. The magic number that defines this “comfortable standard” varies across individuals and countries, but in the United States, it seems to fall somewhere around $75,000. Using Gallup data collected from almost half a million Americans, researchers at Princeton found that higher household incomes were associated with better moods on a daily basis — but the beneficial effects of money tapered off entirely after the $75,000 mark.

Why, then, do so many of us bother to work so hard long after we have reached an income level sufficient to make most of us happy?.....