Some 'classic' money advice is actually pretty new—and not all of it is worthwhile, says historian

In the world of personal finance, many of the lessons we're taught are touted as historical. Since the dawn of time, the experts tell us, those who got ahead financially lived within their means, saved diligently and spent and invested carefully.

It made Joseph Moore — a historian and author of "How to Get Rich in American History," published in April — wonder if Americans had been receiving, following and prospering from the same advice for the past few centuries. What he found surprised him.

"Is there timeless wisdom of money that we should all be following, from Ben Franklin to now? The answer is no," Moore says. "It turns out, what 'always' worked is always changing."

Some common financial principles that seem old are recent phenomena, Moore says, and some situations that seem new are, in fact, quite common throughout history.

In both such cases, knowing your history can be helpful. After all, if previous generations flourished without more recent advice, maybe the current wisdom isn't as valuable as we think. Conversely, maybe you don't need to find a creative solution to a problem that isn't actually that novel.

Here are three misconceptions Moore points out from the history of American personal finance — and what you can learn from them.

Americans are struggling with housing affordability amid high mortgage rates and rising home prices. But it's not a historically unique problem, Moore says.

"We absolutely are in a housing crisis caused by a housing shortage," he says. "It's neither the first nor the worst."

Moore points to 1948, when the ratio of people who wanted to buy a house to available inventory was about double what it is now, as the worst culprit. The year 1981, when the median new mortgage consumed more than half of the median household income, was no picnic either, he says.

That doesn't mean that the current shortage isn't real or that you should suck it up because other people had it worse, Moore says.

But it is worth looking at how people have historically solved it — personally, not politically. And in the case of a housing shortage, Moore's answers aren't glamorous.

One historical solution was moving more often. Currently, the housing market is worse in some places than others. Folks used to be more likely to pick up and go to places where opportunities were better, Moore says. For most of the country's history, between 1 in 3 and 1 in 5 Americans moved every year, he says, pointing to research by historian and journalist Yoni Appelbaum. Now, it's more like 1 in 13, Moore notes.

Another common solution for unaffordable homes: sharing housing. In 19^th-century America, it wasn't at all uncommon for homeowners to rent out rooms in their house to help with the mortgage, Moore says. The same logic applies to modern-day renters who split spaces with roommates to keep costs down, he says.

"It's a shortage of space, so you have to monetize space," says Moore.

Investors are often told that the path to long-term wealth is simple: Invest consistently in a low-cost, broadly diversified stock portfolio. Need proof? Consider the S&P 500's upward trajectory since before the stock market crash in 1929, and think of all the compounding returns you could have earned over that period had you invested.

"Something really new that we act like is really old is that compound interest is what builds wealth," Moore says. "Nobody got rich by compound interest for most of U.S. history, and if they did, they were generally already wealthy."

Think about it: Index funds weren't around, nor were fractional shares. If you wanted to own every stock in an index, you'd need to have the money to buy shares of each, plus a fee for your broker, of course.

"For most of American history, less than 10% of Americans owned stocks at all. That's not how people got wealthy," Moore says. "They got wealthy by concentrating most of their efforts in small businesses and careers, real estate and job tools. [Few people] compounded their way to wealth until the greatest generation and baby boomers, when the technology came online to allow you to use compounding."

Investors should still take advantage of the innovations that made diversified, low-cost portfolios widely accessible, Moore says. Just remember that there's more than one way to build wealth.

One piece of financial advice that feels tried and true is to create a budget and stick to it. How else can you make sure you don't overspend and keep yourself on track toward your financial goals?

But Moore says that the household spending spreadsheet is a relatively new phenomenon.

"Nobody in the 1800s budgeted the way we talk about budgeting," he says. "These forward-facing spending categories would be completely foreign to anyone's thinking."

For most of American history, what folks did instead was look at their money in big buckets. A couple might divide things between the husband's and wife's income, for instance, he says. Or, to keep things even simpler, they divided income between what they needed to survive, and whatever was leftover.

More complex budgeting schemes came into fashion in the early 20^th century, Moore says, with financial guides at the time touting how much you could save by slashing the likes of alcohol and tobacco — the lattes and avocado toast of their day.

There's no one right way to manage money. But if you find budgeting tedious, Moore argues that attitude puts you in line with generations of Americans who kept things simple by practicing what we'd now call reverse budgeting: paying their bills, putting money away for goals and then spending the rest as they saw fit.