Most people purchase new technology merely because it is new, not because they have a particular need for it. Meanwhile all the old technology piles up in their home as junk. A slow battery lessening your phone time?
New model just came out? Don't need my perfectly intact phone anymore! This concept is what is contributing to the tons and tons of electronic garbage created every year. To reduce its environmental effect the least we could do is recycle our old models and use them in the newer ones.