The growing importance of CMOs is reflected in the increasing tenure of the position. A few years back the average tenure of a CMO hit rock bottom at 23 months. But the pendulum is now swinging in the other direction. A recent study by recruitment firm SpencerStuart showed that the tenure has now soared to 45 months, and consultancy Forrester predicts continued expansion of the average to 60 months - 5 years - in 2015.