The days have long passed for using "password," "1234" or "qwerty" as your password for everything.

In fact, it's probably about time you changed your password -- isn't it?

In our world of obscure, probably made up national holidays, May 4 is "World Password Day," a day dedicated to password strength awareness.

Those letters, numbers and symbols are your digital security guards and a "good password," in this ever-changing digital world, could be the difference of having your information stolen and keeping your identity safe.

Partha Dasgupta, associate professor at Arizona State University's School of Computing, Informatics and Decision Systems, told the State Press that "even the most secure system becomes vulnerable because of weak passwords."

So what makes a strong password?

According to TIME, 2016's list of password "you should never use" included such things as "football," "princess," "login," "welcome," "abc123," "admin," "121212," "passw0rd," and "password1."

One expert suggests "going long"  with "super-lengthy sentences that happen to mention the websites name in there." He said long passwords are hard to crack. Another says to add a collection of upper- and lower-case letters, numbers and symbols to the sentence.

It's also a good idea to change you password every few months and stay away from using the same password for everything, Arizona Tech Works says.

MORE: Password “do’s and don’ts,”

So you've created a "good one," what now?

Raise your hand if you've ever forgotten your password. If that's you, then you've probably become best friends with the "forgot password" button or constantly find yourself jotting down passwords in a notebook or Word document.

That could be a huge risk.

"Not having immediate access to your passwords on the go and leaving a paper copy behind, even in your home, is a dangerous habit," Jennifer Jolly wrote for USA Today.

The solution: A password manager, experts suggest.

Managers like LastPass, Dashlane or 1Password will remember passwords for you and can even create strong ones that even you may not be aware of.

USA Today contributed to this story.