Caleb wants to know if it's safe to use the same password across different web accounts. Leo says no, because once one site gets hacked, they can use that password information to guess the passwords for other sites. Many do this, and it's how the Turkish Crime Family was able to hack over a million iCloud accounts. Password vaults make different passwords for every site and you have only one password to open the vault. But that's not on the internet anywhere, he'd just remember that. It's much safer that way.