Two very wealthy sharks from the US version of Shark Tank gave some of the dumbest debt advice I’ve ever seen, which underlines how tips from foreign finance gurus have to be, as the Travelling Wilburys once sang, handled with care!

In principle, everyone needs to be careful of too much debt but to tell people to avoid debt is just plain dumb advice. And to think Mark Cuban and Kevin O’Leary would shovel out such rubbish really surprises me.

So who are Kevin O’Leary and Mark Cuban? Apart from being TV stars, they have a history of making money.

Cuban is an entrepreneur who made his fortune through the sale of start-ups MicroSolutions and Broadcast.com in the 1990s. He later became known as the zealous owner of the NBA's Dallas Mavericks. In 2018, Forbes guessed his net worth at, wait for it, $3.7 billion. And these are US dollars!

Kevin O’Leary is only worth a cool $400 million! He’s Canadian and started Softkey Software Solutions, which was a tech company in the education space. His company became The Learning Company, which was taken over by Mattel, making Kevin a multi-millionaire. He now has the O’Leary Financial Group.

Given these guys’ backgrounds, I take issue with them with a small degree of reservation, but there’s no sense telling a young person trying to build wealth, or even a 50-something who doesn’t own property and has very little in their super fund, to avoid indebtedness and simply save. That’s dumb debt advice!

Imagine someone who took that advice in Sydney and Melbourne five years ago and refused to buy a property.

Both cities have seen house prices spike over 70% over that time. Have a look at this chart to see what happened between the September and December quarters last year:

Have a look at the unbelievable 43.3% gain in prices in Toorak and tell me that those who borrowed for even three months have made a terrible money-making mistake!

Now I have to say what Cuban said about debt and the price you pay makes sense on one level. See for yourself: “"Whatever interest rate you have — it might be a student loan with a 7% interest rate — if you pay off that loan, you're making 7%. That's your immediate return, which is a lot safer than trying to pick a stock or trying to pick real estate, or whatever it may be."

But if that loan turns you into a surgeon and you’re earning over $400,000 a year that borrowing was a wise debt decision. If working hard and studying part-time means you take 12 years rather than six years to be a top surgeon, then you’ve given up six years of $400,000 a year earnings because you’re avoiding debt. That’s dumb!

O’Leary at least has a better time perspective on debt.

“If you want to find financial freedom, you need to retire all debt — and yes, that includes your mortgage,” he told CNBC. And he says being debt free by age 45 is his key rule.

The reason O”Leary says 45 is the turning point is because most people’s careers start in their early 20s and end in their mid-60s. "So, when you're 45 years old, the game is more than half over, and you better be out of debt, because you're going to use the rest of the innings in that game to accrue capital.”

This advice is OK if you’re happy to cruise to retirement and be happy on an OK super income in retirement. However, if you own your own home and have a nice super nest egg growing, that’s the time when many Aussies who pay a lot of tax decide to buy an investment property, using debt, where the interest is tax deductible.

Clearly, this kind of investment comes with the risks of rising interest rates, troublesome tenants, government law changes, economic slumps and even what happens if you lose your job. But this is always the price of trying to get wealthier.

My better advice to anyone who uses debt to grow wealth is to learn about the safe ways of investing and borrowing. Handled with care, debt has become the hallmark of so many people who started with no money but had goals to grow wealth, by working hard and tapping into their vision about people and markets. And, over time, they become increasingly richer.

If Frank Lowy and John Saunders had not had a vision to build a shopping complex in an isolated field in the Western suburbs of Sydney, with their bank manager who lent them the money, they would never have come up with the company name and that business — Westfield — which recently sold for $32 billion!

The smart lesson about debt is not to avoid it but to learn how to use it wisely to build wealth. And it might mean you have to stop being distracted by the silly stories of life that our media machines pump out for the masses, in favour for the stuff we pump out on Switzer Daily, daily.

I know it’s a gratuitous plug but I care enough about you to do such a thing!