Number of the Day: 18
18 -- the average lifespan, in months, of a cell phone in the US, according to Earthworks' Recycle My Cell Phone. At that rate, 130 million cell phones are added to the waste stream in the US every year. Worldwide, according to CNN (and noted here on TreeHugger), global mobile phone use will top 3.25 billion users in 2007. Yikes.