NEW YORK (Reuters) - You do not learn a lot from tax returns, Republican Donald Trump proclaimed in Monday’s U.S. presidential debate.

Republican U.S. presidential nominee Donald Trump rallies with supporters at Orlando Melbourne International Airport in Melbourne, Florida, U.S. September 27, 2016. REUTERS/Jonathan Ernst

Yet politics aside, experts say tax returns are the best way to gauge a person’s financial health.

“From a tax return, you get distinct, discrete financial numbers,” says Jude Boudreaux, a certified financial planner at Upperline Financial Planning in New Orleans. “I can’t imagine ever working with a client and not seeing a tax return. It would limit our ability to provide advice in a meaningful way.”

In fact, many financial advisers ask new clients to provide three years’ worth of tax returns so that they can spot key spending and investing patterns, such as income fluctuations or losses that can be used to offset future capital gains.

“We are able to see the who and the how (of a person’s money), which leads to why,” says Barry Glassman, president of Glassman Wealth Services in Vienna, Virginia.

Disclosure of tax returns is a standard procedure for all modern presidential candidates. Democrat Hillary Clinton’s returns showed that she and her husband, former President Bill Clinton, had $10.75 million in income in 2015 and paid an effective federal tax rate of 34.2 percent.

But as the Nov. 8 election nears, Trump has not yet released his tax returns. He has pledged to do so once the government completes an audit.

With taxes, there are plenty of nuances, of course. Here are three of the key things you can learn from a tax return:

1) Who is part of your financial universe?

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At the very top of your tax return, you have to say who depends on you financially, that includes kids, spouses and even elderly parents.

This information is crucial when it comes to financial planning. You may talk about buying a home or paying a kid’s college tuition, but it will be more complex if you are funding the caregiving costs for an elderly parent or rebuilding your credit after a divorce.

“The very first thing I look at is the filing status,” says John Dundon, an enrolled agent who owns Taxpayer Advocacy Services in Denver, Colorado and blogs (johnrdundon.com). “If (clients) are married filing separately, perhaps their finances are so complicated they don’t want to be held accountable for each other’s obligations.”

2) How much do you earn?

Simply put, you pay taxes on income, and a tax return amalgamates all of the sources of that income, be it your job, your investment portfolio, real estate, partnerships or other sources.

Aside from normal wages, the first big chunk of your 1040 tax form (Lines 7 through 22) is a financial snapshot of income-oriented sources, including dividends, alimony, rental income, Social Security and other retirement benefits.

Knowing what a person earns is helpful, but understanding where the income is coming from is the cornerstone of a financial plan, says Diahann Lassus of Lassus Wherley, a financial planning firm with offices in New Jersey and Florida.

“What is the largest source of income? Is it earned income or a trust they don’t have any control over? That can drive a lot of the other information,” Lassus says.

3) What kind of deductions do you have?

The next big chunk of your tax return reveals a lot about the financial obligations you have as well as the money decisions you make. If you itemize deductions, you can see information about home ownership, charitable donations and medical expenses.

For example, if you own a small business, you may not be saving for retirement. That is a big no-no in the world of financial planning. You could be paying hefty interest on student loans, a red flag that you are drowning in college debt. And you may be giving money to dozens of charities, rather than donating money in a thoughtful way for the most impact.

By contrast, you could be a financial adviser’s dream client and list the thrift store prices of clothing donated to charity. “When we see those things, we can get a sense of how meticulous that person is and their attention to detail,” Glassman notes.

That is why financial advisers read between the lines of your tax return. “I’m looking at it for audit potential,” says Alan Pinck, enrolled agent from San Jose, California. “We have to show how people live, if they have no taxable income.”

(The opinions expressed here are those of the author, a columnist for Reuters.)