Last Wednesday, Dr. Katy Votava, founder and president of Goodcare.com, presented a one-hour webinar on Health Savings Accounts (HSAs): Myths, Misconceptions, and Practical Uses.

"We don't have any [other type of] account like this," she told several hundred online participants.

HSAs, she explained, are the most tax preferred savings accounts available in the U.S. Launched more than a decade ago, they act like a personal bank account but with a few key differences. First among them: money goes in tax-free, grows tax-free, and comes out tax-free if used for qualified medical expenses, the definition of which is extensive.

"To have an account, you have to have a certain type of health insurance," she said. Generally, that's a high deductible plan, but not all high deductible plans are HSA eligible. It's a good idea to check in advance.

Another key benefit, she said, is that "it's not a use-it-or-lose-it account." If, for instance, you change health plans to one that is not HSA eligible--perhaps when changing jobs, say--you can still use the funds accrued in the HSA. "But you cannot contribute new dollars," if you no longer have an eligible health plan, she added.

You also cannot contribute if you are "claimed as a dependent on someone else's tax return," she said, or if you're enrolled in Medicare. Anyone who receives Social Security benefits is automatically enrolled in Medicare part A and, thus, not allowed to contribute to a HSA.

As with any personal savings account, HSAs are custodied at a financial institution, and you can pick the institution (there's a broad variety these days). Most don't have an annual fee, although she notes that many of them used to, so be careful. You might choose your own bank or, if you're making contributions through a payroll deduction, consider your employer's bank. There's now a wide assortment of investment options, too, so choose carefully.

Yet there are contribution limits. Last year the maximum individual contribution was $3,350, and contributions through April 15, 2017, can count toward 2016's limit. This year the individual maximum is $3,400. The maximum family contribution remains at $6,750. "That's pretax," she noted, a benefit that clients are "picking up at the go-in." Contributions up to the annual limit can be deducted from federal income taxes and from many states' taxes, too. "Check out your particular state," she advised.

Additionally, those who are 55 or older can contribute an extra $1,000 per person per year (but married couples cannot add $2,000 to a shared HSA; instead, each spouse can add $1,000 to his or her individual HSA).

Note that if employers (or loved ones) make contributions for their employees, it doesn't count toward the employee's individual tax deductions.

Employees who contribute through a payroll deduction can designate the amount and change it throughout the year. They can also contribute separately on their own by mailing a check or in a number of other ways. One recommendation Dr. Votava mentioned is an IRA direct rollover, a one-time-only opportunity to transfer funds to a HSA without an IRA distribution penalty or tax.

She cautioned, however, that HSA regulations are constantly in flux. So it's crucial to stay up to date by. Follow her updates on social media. She also pointed listeners to several government publications that lay out specific rules. Among the fine print: contributions in excess of the annual limit incur a 6% penalty, though that may be reversed if the mistake is reported promptly. Withdrawals spent for nonqualified purposes trigger a 20% penalty.

In the final 15 minutes, Dr. Votava took questions. One concerned 401(k)s. She recommended first filling your HSA with enough to cover your deductible, then contributing to a 401(k) to maximize an employer's matching contributions. After that, you can contribute more to the HSA till you've reached the annual maximum.

She also explained that there's no time limit for reimbursing yourself for a qualified medical expense. You could even keep a receipt for several years, to allow the HSA to keep growing, and only withdraw the funds when you hit a cash-flow snag.

Dr. Votava will present at two upcoming conferences in Dallas: "Hot Topics in Health Care: Invest in Women" (May 9-10) and "Health Care Planning for Retirees in an Uncertain Environment" (May 11-12).