Scattered among the typical security question options is passport/ID number. While it’s not something you’re likely to post on Facebook (unlike favorite animal or holiday destination, perhaps), it isn’t something that is a secret: very often people are asked for their passport numbers when registering for hotels, for example. In addition, I have always been given a new passport number when I renew my passport. Will I always know which passport number I used? Will I still have access to it?