To help the environment...
Today mobile phones have become more than a means to simply communicate, they have become a sophisticated device more like a computer with the ability to surf the web, get email and socialize with your friends. Every year they are becoming more powerful 'must have' devices which has now led to a surplus of unwanted outdated technology that cutting edge consumers discard.
Recycling your old mobile cuts down the surplus of old phones and allows them either a new life mainly in developing nations or to be broken down for the valuable materials they contain to be reused in new technology.