Now that so much of lives are tied to mobile phones, one of the key things to do is to protect yourself against number porting thieves. This is a dastardly plot where an identity thief gathers enough personal data (SSN, Mothers Maiden Name) to be able to port your number. Then suddenly all of your two factor authentication breaks and they can take control bank and other accounts.
The solution is to lock your porting. At T-Mobile for instance, you can set a separate porting 6-15 digit pin by calling 611. It’s a great thing to stick inside your password