The Gentle January series shares one practical privacy tip a day from a Markup staffer who actually uses the advice in their own life.  

I’m one of those people who always arrives at the airport many hours before flying. I anticipate I’ll encounter every potential hiccup that could prompt a delay, like agonizingly slow conveyor belts at security, or making my way to LaGuardia only to realize I’m actually flying out of JFK. Better safe than sorry.

Instead, what usually happens is that I spend lots of my airport time sitting at the gate, or the food court, idly trying to kill time. In these moments, a cherished pastime is reading whatever’s on the computer screen of the person next to me. Mostly I see nothing super interesting, just aimless Twitter scrolling or a fun movie. But occasionally I get lucky and see more exciting stuff: drafts of break-up notes, juicy roommate arguments conducted (puzzlingly) via Snapchat, bank statements, and, more than once, internal materials from companies or agencies I’m interested in as a reporter. This kind of peering, when used to actually steal information, is known as “visual hacking” or “shoulder surfing,” and research sponsored by 3M (which sells screen protectors) found this kind of hacking is successful 91% of the time.

Fortunately, I don’t use my powers for evil. But fear of having my own screen seen is the reason I don’t go anywhere without a privacy protector for my computer and phone. This is true especially when I am communicating using a platform designed to keep sensitive messages secure. The protectors work simply, by obscuring the view of your screen—unless the nosy party is standing or sitting directly behind you. They tend to be pretty affordable, don’t take long to get in place, and can last a while, especially on a laptop.

You can find a roundup of well-reviewed privacy protectors on tech news platform Futurism and at consumer-advice site Spy.