Do not take financial advice from food delivery services.

When DoorDash recently announced that it was joining Grubhub in allowing customers the option of paying for their delivered meals in four installments, it served as a reminder of one of the fundamental steps in accumulating wealth: never borrow money to pay for consumables.

Food is the ultimate consumable. Food from DoorDash, with its added convenience fees and markups, is a premium consumable.

It’s a shocking shame, but people will use the instant credit offered by these delivery services, not realizing they are stepping onto a financial treadmill. And for many, it will be the beginning part of a cycle that will almost guarantee a lifetime of financial struggle.

Most wealthy people don’t become wealthy as a result of massive incomes, inheritance, taking advantage of others, or winning the lottery. (Have you ever noticed that when the lottery jackpot reaches a billion dollars the convenience store parking lots are not full of Mercedes?) People accumulate wealth based on how they spend money, not just how they earn it. People who borrow money for clothes, vacations, gifts, and delivery tacos aren’t accumulating wealth. Instead, they are accelerating their future consumption to the present, which will force them to either reduce their future consumption or commit to a lifetime on a treadmill of debt.

And the older you get, the faster that treadmill runs.

In addition to never borrowing money for consumables, another key to accumulating wealth is to spend less money than you earn. Simple, but for a lot of people, it is incredibly difficult. The best time to begin saving money is now. The easiest time to begin saving money is when you are only a step or two above broke. Too often, young people decide they will begin saving at some point in the future, when they are making more money. If you can pay your bills but you are still poor, what difference does it make if you are slightly more poor? The act of saving, even if only a minimal amount, will begin to build a habit that will pay increasing dividends over time.

Wealth, for the most part, isn’t created through luck, timing, or exploiting others. It’s built through repeated smart choices that eventually become habits. The value of those habits accumulates and compounds over time.

Likewise, the opposite of wealth is built through repeated dumb decisions that also become habits and accumulate over time.

Building wealth starts with a few simple truths – one of which is that if you have to finance your takeout food, you can’t afford it.

David Moon is president of Moon Capital Management. A version of this piece originally appeared in the USA TODAY NETWORK.