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Time is finite, money is not: The concept of marginal utility tells us that when you’re hungry, that first slice of pizza brings considerable satisfaction. As more slices are consumed, however, the joy experienced at the onset tends to plateau. This same theory can be applied to income and money. In fact, a recent study shows that happiness from additional income flatlines after a salary of $105,000. The presence of additional income brings you upgraded items and experiences, but that extra income also often comes at the price of giving up more time.

At what cost? As Raines says, “The most powerful opportunity cost in the world is what we choose to do with our time.” You don’t get your time back. And in that light, he advises three points to follow: Find your “enough” (the amount of money you need to live a fulfilling life), invest (to grow more money and create more time) and just make more (money, that is, by budgeting or even taking on a side hustle).

Pinpoint your “enough”: Knowing your number can be one of the most powerful and simplest exercises you can do to find happiness in life. The sooner you do it, the better off you’ll be.