Earnings

The amount of money that you can make varies from career to career.

A 2013 report by the Economic Policy Institute estimates the income level necessary for families (with two parents and two children) to secure an adequate but modest living standard at between $48k and $94k depending on broad geographic location (not counting money put into savings).

A 2010 study published in the Proceedings of the National Academy of Sciences found that emotional well-being increases with household income up to $75k/year but no further, and that life satisfaction increases with household income up to well beyond $120k/year.

Some things that extra money can be useful for are:

• Geographic flexibility — You can use additional money to live in areas with higher cost of living.
• Raising children — You can use additional money to pay the financial costs of raising children.
• Donating to charity — You can use additional money to donate to charity.
• Luxury spending — You can use additional money to buy luxury goods and experiences.
• Liquidity — You can use additional money to cover unexpected expenses (such as medical bills), or to retire early.
• Social influence — You can use additional money for social influence – for example, by making ear-marked donations to community organizations that you're a part of.

Geographic flexibility

Economic theory predicts that the more desirable a location is to live in, the higher the housing cost is there. For example, a recent survey found that New York City is the city in the United States that people collectively find to be the most desirable, and ApartmentList.com reports that New York City has the second most expensive housing in the United States. The cost of renting an apartment for a two parent, two child family ranges from ~$600/month in certain rural areas to ~$4000/month in Manhattan, New York.

So your ability to live in a desirable location depends a lot on your income.

Raising children

The US Department of Agriculture estimates that the cumulative cost of raising a child from birth through age 17 (for a two-parent middle class family) is ~$240, not counting the cost of higher education, which averages ~$60k for public colleges and ~$120k for private colleges.

Having more money enables you to comfortably raise more children.

Donating to charity

Middle and upper class people in developed countries such as America have the opportunity to contribute outsized social value by donating to charity. There are families in Kenya that live on $1000/year — this is about 50 times lower than median income in the United States. By donating ~$1000 to GiveDirectly, which transfers cash to poor Kenyans, an American can double the consumption of an impoverished Kenyan family for a year.

There may be charitable giving opportunities that are far more impactful than GiveDirectly, but GiveDirectly establishes a minimum amount of social value that you can contribute by donating to charity.

The more money you have, the more you can donate to impactful charities such as GiveDirectly.

Luxury spending

LearnVest estimates points out that

• Some people want expensive homes, or luxury homes, which can up to double one's housing expenses (say, bumping one's cost of housing up by ~$30k/year.)
• Luxury cars can cost ~$40k more than inexpensive but functional cars.
• Hiring a nanny can cost ~$30k/year
• Designer clothing can cost up to ~$20k/year
• Eating at expensive restaurants, taking up expensive hobbies such as sailing, and attending lavish events can cost ~$25k/year
• Traveling to exotic locations several times a year can cost ~$15k/year

If you want a lifestyle that includes all of these things, you need an additional ~$130k/year after taxes.