Grant Cardone has 1 rule for families on their way to wealth. Once you hear it, you'll rethink every purchase you make

Grant Cardone buys a lot of things: Cars, real estate, businesses. But there's one test every purchase has to pass first, and it has nothing to do with whether he wants the thing or can afford it.

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"If I can't write it off, I don't buy it," the real estate investor, author of "The 10X Rule" and CEO of Cardone Capital, said in a (1)TikTok video (1). "I will not spend any money that cannot be written off."

And Cardone wants regular households to follow his lead. "If you want to make a simple rule for your household — if we can't write it off, we're not buying it. If the federal government doesn't allow me a tax reduction, we are not going to do this," he said. "When I buy a car, I don't buy the car I want. I buy the car that I can write off."

It sounds extreme. It is extreme. But the thinking behind it explains how wealthy people treat money differently — and there's a version of it that works for a normal family budget.

A tax write-off (or deduction) is an expense the government lets you subtract from your income before calculating what you owe. Spend $10,000 on something deductible, and your taxable income drops by $10,000. Spend the same money on something non-deductible, and you pay tax on every dollar first, then spend what's left.