A Dollar Spent Today Costs About $15 in Retirement
Left alone at 7% a year, money grows about fifteenfold over 40 years.
The Diary Of A CEO with Steven Bartlett · Stock Expert: Becoming Rich Is Simple, But You Won’t Do It!Leave $10,000 alone in stocks earning about 7% a year, and in 40 years it becomes about $150,000. That is the math financial advisor Ben Felix uses to reframe every purchase, and it means a dollar spent today costs roughly 15 dollars in retirement.
The engine is compounding, or growth building on growth. Start with what stocks have delivered in the past and what they might reasonably be expected to deliver, around 7% a year over the long run. Cash sitting safely in a bank might pay about 2%, so holding cash instead of stocks gives up about five percentage points a year.
That gap compounds into a very large cost over decades, which is why avoiding stocks entirely or holding too conservative a portfolio leaves so much gain on the table. The $150,000 figure comes from compounding the full 7% stock return, to show what invested money becomes if you leave it alone.
Shrink the example down to daily life and the tradeoff gets vivid. A $10 coffee, invested instead at 7% for 40 years, would become about $150. A $10,000 car, if the money were left invested instead, would become about $150,000. Counting all the growth the money would have earned, not just the extra over cash, the true price tag is 15 times the sticker price.
The takeaway is not to buy nothing. It is to ask whether the spending adds enough to a good life to be worth 15 times its price in future money. A coffee you gulp while rushing to work, and barely taste, probably fails the test. One you slow down for, savor, and remember, just might pass it.
Questions people ask
Is 7% guaranteed?
No. Seven percent is a long-run average expectation based on past stock returns, not a promise. In any single year stocks can fall sharply, which is why Felix frames the 7% as what you might earn if you stay invested for decades.
Does this mean I should never spend money?
No, and Felix says that math should not paralyze you. If a car lets you reach a better-paying job, or a coffee gives you real pleasure or time with a friend, that present value can outweigh the future money forgone. The point is to cut spending that adds little to your life.
Why use 40 years?
Forty years is roughly a working life, say from age 25 to 65, so it shows the full power of compounding. Shorter periods still multiply money, just by less. At 7%, $10,000 becomes about $76,000 in 30 years and about $38,700 in 20 years.