You should enable Find My iPhone

Apple's Find My iPhone feature is amazing. Not only can it help you find your lost iPhone or iPad, if you have it enabled it also stops thieves from being able to use your phone as their own. Every time an iPad or iPhone is reset and restored as new, it must check on the internet to see if the phone is registered with Find My iPhone. If it is, the phone can not be used without the Apple ID and Password that were used.

To make Find My iPhone even more usefull, enable Send Last Location (iOS 8 or higher). This will make your device log it's location with Apple just before the battery drains completely. Which would be a big help if you can't check the website before your phone runs out of juice. To enable Send Last Location,

1. Open the Settings app.
2. Click on iCloud.
3. Click on Find My iPhone (or iPad)
4. Make sure both Find My iPhone and Send Last Location are turned on (green)