Chief executives, like professional football managers, have a shelf-life. The tricky part is knowing when your time is up.
Bob Dudley, the chief executive of BP, capped a week of departures at the top of Britain's largest companies last week with the news that he would retire in February after 10 years at the helm.
Dudley's announcement followed those of peers at Tesco, Imperial Brands, Standard Life Aberdeen and Metro Bank.
The year is shaping up to be a record for churn among the bosses of UK-listed companies.
Life at the top is getting tougher. Increased scrutiny from investors, regulators and the public have made the role more demanding than ever.
Overall, the median tenure of UK CEOs has been declining since 2010, according to a recent study by consultants PwC. The median in 2018 for outgoing corporate chiefs was 4.6 years, down from 8.3 years in 2010.
The picture is similar on the other side of the Atlantic. A study by Equilar recorded the median tenure for CEOs at S&P 500 companies as five years at the end of 2017.
The back story to every departure is different but last week's rash of exits illustrates one important lesson for corporate leaders: timing your departure right can do wonders for your legacy.
As with football managers — and politicians — many executives' corporate lives end in failure. Overextending your tenure often goes wrong.
It was a lesson learnt the hard way by one of Dudley's predecessors at BP. Lord Browne, who earned the sobriquet the "Sun King" after transforming the oil group through a series of blockbuster deals, fell from grace and was forced to resign after 12 years at the helm.
Dudley, for his part, deserves plaudits for steering the company to recovery after being on the brink of bankruptcy in the wake of the Gulf of Mexico disaster and rebuilding itself. The American has been handsomely rewarded, but BP's shares have risen 23 per cent since 2010.
If 10 years is the right time for Dudley, for Dave Lewis, his counterpart at Tesco, it is rather fewer. His reason for leaving is simple: he has done what he set out to do after arriving in 2014.
It is a case of "mission accomplished" after he met the targets, including cost-cutting, restoring profit margins and rebuilding customer trust, that he had set himself. The two cases underline that there is no perfect length of tenure.
History has shown that company lifers, along with founders, often cling on too long. Their knowledge of the business and leadership skills should rightly be valued, but the time comes when being in the job too long starts to hurt the company.
Longstanding CEOs can grow too close to buyside analysts whose backing of management can make it more difficult for board members to challenge them.
For any departing CEO, history also holds one salient piece of advice: your legacy may look secure the day you leave but time can expose hidden failings.
Terry Leahy, a long-serving predecessor of Lewis at Tesco, was similarly showered in plaudits when he stood aside in 2010. Yet when the business ran into problems a few years later, Sir Terry's critics charged that he had overexpanded, notably in his failed pursuit of growth in the US, and been too aggressive with suppliers.
The short tenure of his successor, Philip Clarke, also raised questions over succession planning.
One answer is to extend the emerging practice of paying senior managers partly in stock which they must hold for a certain period after leaving. That at least makes sure that ex-bosses share some of the pain if things go awry while they are enjoying the fruits of their labours.
Written by: The editorial board
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