If you lose your phone, a new study found that having your contact info on your lock screen triples your chances of getting it back. If you have an Android, there should be a way to do it in your settings. If you have an iPhone, do this! "Find My iPhone" has a way to do it AFTER you've lost the phone. Log into iCloud.com. His "Find My iPhone". Set the device to "Lost Mode". It'll allow you to put in a phone number and a message... it'll then display that message on your lost iPhone! Cool little hack for ya.