Most people change cell phones every two years. If you have a lot of phone numbers on your old phone., It is a pain to transfer the numbers into the new phone. Also, in case the phone is lost or broken, you should back up your phone numbers. Most of Chinese use Moto V3 these days, the best way to back up v3 is to buy Moto phone tool software and USB. You can buy it at amazon for $6. Here is the detailed infor: how to transfer or back up your phone numbers