We work for money.
We trade money for luxuries and experiences, in other words, happiness.
There is always a trade-off between investing and using money, trading today’s happiness for tomorrow’s happiness.
If we are trying to maximize our life for happiness, the focus will be on current happiness until a certain point. At a certain point, the more money that is spent results in less and less happiness. Knowing what that point is, helps to determine the point where we switch from using our money for current happiness to saving money for future happiness.