Windows Phone 8 Basics - Find a lost phone - To change settings for Find My Phone

You can set up Find My Phone to save your location every few hours or to use push notifications instead of text messages to send commands (and apps) to your phone faster and more cheaply. Change these settings on your phone, not on your computer.

In the App list, tap Settings Settings icon, and then tap Find my phone.

Select either or both of the following:
Send apps to my phone using push notifications (not SMS). The Find My Phone service and the Windows Phone Store on the web use text messaging to send commands and apps to your phone. Check this option to use push notifications instead. Why? Push notifications can be faster than text messages, and if your mobile operator charges you for each incoming text message, push notifications might also be cheaper. Also, My Phone can only send 15 text messages to your phone in a three-day period. With push notifications, there's no limit.

Save my phone's location periodically and before the battery runs out to make it easier to find. Microsoft can save your phone's location details every few hours so that if your phone is out of range or the battery dies, we can still show your phone's last known location on a map.