How much money is enough? We're obsessed with this question, aren't we? Research has found that there is a connection between wealth and happiness, but only up to a limit. The beneficial effects of wealth taper off almost entirely once a comfortable living standard is reached.

This living standard would obviously be different across individuals, cultures, and economies. What almost everyone agrees with however, is that it would be inefficient use of our time accumulating wealth that we never use. Wealth, among other things, is only a means to an end. We should earn it as much as we need and no more.

It is common to see this theory, and advice based on it, in popular media. This one, for example, was recently in the news. What I haven't yet seen is a mathematical analysis, even a simplistic one, to come up with a formula for this amount—wealth that we need to comfortable retire and never having to worry about money at all—commonly known as FU money.

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