|That sinking feeling when...|
I chose a free app called Lost Phone. After you've installed and configured it, it provides a few very nice capabilities, all commanded remotely by sending a text message to your phone. You can remotely set the ring mode to normal and increase the ringer volume to max; useful for those times where you're sure the phone is somewhere nearby but just hiding under or behind something, and probably with the ringer set to silent. Like like that time it fell out of your coat pocket while you were getting up out of your seat at the end of the movie. (Or are you one of those
Then there are the times when it really is lost, like when you left it lying on the table at the restaurant and another customer picked it up, deciding that yippee hooray he had just acquired a new phone. For these situations you can send a different message to your phone that locks it, requiring you to enter your password to unlock it. When it's locked it doesn't operate, but instead simply shows a message stating that the phone is stolen and would you kindly call one of these people at one of these numbers to arrange its return. Also, if a new SIM card is installed your phone will begin sending text messages to a list of phone numbers that you have configured in. These text messages will have the phone number of the new SIM card, helping you track down the new "owner" of your phone, and allowing you to still control it remotely even though its phone number has changed (which I think is very cool). Of course, whoever takes your phone might connect a cable to it and do a factory reset, which will wipe our your Lost Phone app. But it will also wipe out all your very valuable personal data. Because of this, the lock feature of Lost Phone is probably more useful for protecting your data than for getting your phone back. But you never know.
A third option is to send a message that causes the phone to start sending text messages containing its GPS coordinates. Very handy if you've left the phone in a place where there is nobody to hear it ring. (That little trail down to the river, that runs off the main hiking trail, where you laid your phone down to tie your shoe. Remember?)
Lost Phone is not the only app of its kind. It's not even the only free app of its kind; a really quick search on the Google Play store turned up at least 3 freebies. I've not checked, but I would be surprised if they don't also exist for the iPhone.
I've crossed #12 off my list of Sinking Feelings. You should, too.