What is a "passphrase"?
A passphrase is a type of password that consists of multiple words that may form a sentence or other series of words in a certain context that is easy to remember for the user.
Are they as secure as traditional passwords?
Yes. As they tend to be longer than a password, that additional number of characters makes them more secure. To test this, check out Kaspersky's password complexity checker (DO NOT put real passwords into the tool).
What should I avoid when making a passphrase?
As with any password, you should avoid selecting a passphrase that is easily guessed by another. For example, if you have a favorite quote that you use on social media or frequently in conversation, that quote would not be a good choice as a passphrase for your accounts. You should also avoid common phrases like those in nursery rhymes and popular song lyrics.
Do passphrases have any drawbacks?
Because a passphrase's security typically comes from its length, passphrases can be cumbersome for anyone who needs to enter their password frequently throughout the day. For example, an average typist logging into a device or service twenty times a day using a forty character passphrase will lose between ten to fifteen minutes a day in password entry. Always consider how using a long passphrase will impact your day before selecting one, and compensate for any reduction in length with an increase in complexity (such as exchanging letter characters with special ones).