Two things are a must for your smart phones.
This way if a Good Samaritan finds your phone they can contact you so you can get it back.
In the Apple world, remember to back-up to your iCloud and turn on the locate feature in your settings.
For Android, go to the Play Store and get
https://play.google.com/store/apps/details?id=com.fsp.android.phonetracker
May 17, 2017 – On older devices you can go to the Google Settings app, and then tap on Android Device Manager. To enable remote data wipe, tap on the box next to “Allow remote factory reset,” then tap Activate. Should your phone ever go missing, you can track its location and remotely lock or erase it.