Recently, I had the pleasure of recording one of my favorite podcasts. The host asked what sounded like a simple question:
“What’s the biggest financial mistake you’ve ever made?”
There were three or four of us on the panel, and as we went around the table, each person shared a story about a purchase they regretted. One person had splurged on a car they didn’t need. Another had upgraded a home too early. And the reason each one labeled it a mistake was the same:
They ran the math. “If I hadn’t bought that thing 15 years ago and had instead invested the money, it could’ve compounded into hundreds of thousands, maybe even millions, of dollars by now.”
That’s the familiar logic of opportunity cost: the idea that every dollar you spend today robs your future self of what it could have become.
We hear this all the time, especially in the personal finance and FIRE (Financial Independence, Retire Early) community. Opportunity cost gets used as evidence that we should be frugal, that we should align spending with our values, or that every indulgence is some moral failure against compound interest.
But here’s the thing: after years of thinking about money, and after watching people in the financial independence space tie themselves in knots over these hypotheticals, I’ve come to believe that opportunity cost is kind of bullshit.
At least, the way we usually use it is.
And there are two big reasons why.
1. The Infinite Treadmill
The first problem is that opportunity cost, when taken seriously, becomes a kind of logical black hole.
“If I hadn’t bought that thing,” we tell ourselves, “I could’ve invested the money, let it compound, and I’d have millions now. Then I could buy whatever I want.”
Sure. Except, if you don’t buy what you want now, those millions could eventually become billions…and then you could really buy whatever you want. And if you hold off another 30 years, maybe those billions could become trillions.
You see where this goes.
Opportunity cost never ends. It’s a treadmill that tells you the smart move is always to delay gratification forever. You should never spend money now, because future-you could always be richer.
But the entire point of money isn’t to watch it multiply indefinitely. The point is to use it. To convert numbers on a screen into something that makes your life better, more meaningful, or just more fun.
Yes, ideally you spend on things you value, but that’s not the same as never spending. At some point, you have to bite the bullet, spend the money, and, as horrifying as this may sound to the optimization crowd, suffer the “downside” of opportunity cost.
Because otherwise, what’s the endgame? You die with a portfolio that could have become slightly bigger had you lived another hundred years? Congratulations, I guess.
2. It Doesn’t Matter When You’re Already Doing Fine
Here’s the other reason I think opportunity cost is mostly nonsense: for many of us in the financial independence community, it literally doesn’t matter.
I hear people — people who already have millions in the bank — say things like,
“I wish I hadn’t bought that car. If I’d invested the money instead, it could’ve compounded and been worth so much more today.”
No, it wouldn’t have.
You already have millions of dollars. You’re financially independent. You’re fine. That one purchase didn’t make a dent in your long-term trajectory. Whether that $20,000 went into a mutual fund or into a car doesn’t change the fact that you’re still financially secure today.
Opportunity cost only matters when the lack of money actually limits your life. When you’re broke, sure, it stings to look back and think, “If I’d invested that money, I’d have more options now.” That’s real.
But once you’re past the point of basic financial security, once you’ve already “won the game”, opportunity cost becomes a ghost story. It’s a way to guilt yourself about spending money you could absolutely afford to spend.
You’re not missing out on anything. You’re not less wealthy in any meaningful way. You’re just human, and you bought something you wanted.
That’s it.
The Real Cost Is Zero
When people talk about opportunity cost, they often imagine some dramatic alternate timeline: the version of you who didn’t buy the car, didn’t go on the trip, didn’t upgrade the house — and who now sits on a mountain of extra money, smugly sipping a green juice.
But that fantasy ignores the obvious truth: that version of you might not even exist. Maybe you wouldn’t have invested that money anyway. Maybe you would’ve spent it on something else. Maybe the joy you got from the thing you bought was actually worth the tradeoff, even if the spreadsheets can’t capture it.
At some point, you have to stop using opportunity cost as a moral weapon against yourself. You spent the money. You’re fine. You’re probably better off for it.
Stop Worshiping the Counterfactual
Opportunity cost is seductive because it sounds so rational and so economically pure. But it’s really just a way of measuring your life against an imaginary version of yourself who always made the optimal financial decision.
And that person doesn’t exist.
Money is not an abstract math problem. It’s a resource meant to be converted into experiences, security, connection, and yes, sometimes just comfort or joy.
So when you look back at that “big” purchase and start calculating what it could have been worth if you’d invested it instead, try this: don’t.
You spent the money. The world didn’t end. You’re probably still on track for every financial goal that matters. The opportunity cost to you, in reality, was zero.
In other words: stop letting imaginary compound interest bully you. Spend your money. Live your life. That’s the actual point.
Did you catch this week’s episode of Earn & Invest (Click to listen)?
The Purpose Code is Now Available!
