Sir Alex Ferguson retired after 27 years as Manager of Manchester United and an impressive number of Trophies and Awards. To put this achievement in perspective:
The next longest serving Manager was Arsene Wenger, who would need to stay at Arsenal for another 10 years to beat Sir Alex Ferguson tenure
The average tenure of a Premier League Manager is 2.67 years as opposed to 1.96 years in the Championship in the last full Season. Interestingly the lowest tenure recent was 0.89 years in the Championship in the 2010 to 11 season.
In a recent survey, 76% of employees changed jobs within 3 years with a peak after 2 years. With recruitment, induction and training, this can be a significant investment. Like Football, new recruits can change the team as well as themselves. Lack of personal and career opportunities, was given by employees as the most common reason for leaving. Investment in recruiting and then managing employees is good practice and a good investment.