MILWAUKEE (CBS) – Experts say the recent massive data breach at Marriott hotels is another reminder to keep a close eye on your personal information.

500 million people’s personal information was stolen over a four-year span from the Starwood branch of the Marriott Hotel chain.

The information that was stolen included names, addresses, phone numbers, emails, and even passport numbers.

Credit card numbers were encrypted, and Marriott says it’s possible they were also compromised.

“All the info that a crook could use to spin up a credit account in your name,” said Ted Rossman, an industry analyst with creditcards.com.

“It’s really big in terms of the number of people it impacts,” said Kevin Bong, a cybersecurity expert with Sikich LLP.

If you stayed at any Starwood Hotel branch in the last four years, your information was exposed.

“I think this is another wake-up call to work a little harder, be a little more diligent, be a little more wary,” said Bong.

It’s become almost common to have these huge breaches. Experts are surprised there aren’t more, and say your information is eventually going to end up being stolen.

“The risk is still the same because our information is already out there, we just have to act like it’s already out there and continue to be wary, continue to not trust things that don’t seem trustworthy,” said Bong.

So what are some ways to protect yourself?

“Getting your credit report regularly, making sure there aren’t any new accounts on it, monitoring your credit card bill every month,” said Bong, “changing your passwords.”

“I’m pretty careful about what I put out there,” said Jorge Cossio who was traveling from Milwaukee to Green Bay.

Cossio says he keeps a close eye on his information. “I watch and I have triggers here and there to let me know if someone is looking at my info,” said Cossio.

If you think you’ve been breached, Marriott has set up a website with links to protect yourself.