Researchers at Princeton University who polled 450,000 people several years ago found the optimum income amount for most seemed to be about $75,000 a year.

RomarioIen, ThinkStock
RomarioIen, ThinkStock

The study by economist Angus Deaton and psychologist Daniel Kahneman seems to suggest that one's life condition, in general, gets worse below that $75,000 income level as so-called "disposable income" diminishes. Their research, published in 2010 and brought to light again this week by a Seattle CEO's decision to raise his employees' minimum wage to $70,000 per year, also indicates that both marital and health issues magnify when income is below that $75,000 threshold.

However, Deborah Carr, professor of sociology at Rutgers University, argues that "a lot of us don't need luxury. We just need the minimum it takes to provide food, shelter, (a) car and the basic things that we need to get through our day."

So, why is that $75,000 figure a benchmark? According to Carr, there are a couple of reasons.

"I think the first is that that is probably the minimum one needs to lead a happy life, where they have suitable shelter and food and access to the basic goods that they need," she said. "Any dollar above $75,000 a year probably will not have a huge impact on how satisfied one is in their everyday life, because it won't buy them many more necessities, really. It will simply buy them more luxuries."

Carr said it really is not luxury that puts most people over the edge of being tremendously satisfied. She makes the point that many of us are what she terms "biologically happy," regardless of income.

"Some of us are happier than others regardless of the circumstances, and the same holds for very rich people," she said.

Commenting on the Princeton University study, Carr said from her perspective, there are really two main findings.

"One, that happiness really is something within us," she said. "Some people really just have a temperament that makes them happy, and no matter how much you give them or take away, they will still be happy. Two, when it comes to how you feel about your everyday life, are you satisfied with what you have and where you are going? And in that case, money can buy you happiness to the extent that it buys you the necessities that you need to get through the day."