As Tax Day approaches, experts are offering taxpayers tips to avoid scams.

Susan Letizia of SEL Tax Services says people should be careful who they share their tax returns with -- it can lead to identity theft.

"Your whole life is on there," she says. "Your name, your dependents, your bank account -- everything."

The biggest red flag is when someone claiming to be from the IRS calls or emails you with threats.

Whoever you have file your taxes should be trustworthy and work for a reputable company, Letizia says.

That said, you should check your tax return afterward.

"A real good giveaway to a person that's not reputable is when you look at the bottom of your tax return it says 'self-prepared,'” Letizia says. "They didn't sign their name. They didn't put a PTIN."

A PTIN is the preparer tax identification number -- which tax preparers are required to use on all federal tax returns.

"What happens is they deposit your refund into their bank account," Letizia says. "They leave without a trace. You don't know who they are. They disappear."

Zack Martinez, a certified public accountant, says he keeps track of new tax scams every year.

One new one involves phony tax preparers who file your return.

"Then [they] call you pretending to be the IRS, saying there was a mistake in the refund and you need to send it to them," he says. "Instead of sending it to the IRS, you're sending it to the scammers."

The bottom line, he says, is to know who's doing your taxes and double check your returns.