It seems like every week, a new company has to notify its customers that their data may have been compromised, and personal information may have been affected.

Data breaches can happen for a variety of reasons. Some companies are hacked. Data can be mishandled or sold to third parties. Holes in a website’s security system can leave information unprotected.

One of the latest victims was Marriott hotels, which recently revealed that hackers had accessed the information of an estimated 500 million customers.