So the job of making the CEO role sustainable is not a "nice to have" for the CEO, it is a "must have" for the organization. There are three issues to consider:

1. The right governance to create an institutional sustainability plan: The best CEOs sweat governance to make sure that the core sustainability of their institution is not dependent on the personal sustainability of the CEO. This means that the board plays its role—addressing the strategy, addressing the people, addressing the risks in a regular and consistent way. It also means the executive committee plays its role by cycling through the company's most most important sources of value, ensuring they are on track, identifying risks and developing risk-mitigation plans.

2. Personal sustainability plan: Having established the right institutional governance, the best CEOs do worry a lot about their personal sustainability. Many first-time CEOs, however, ignore it. They have aspired to the CEO job for years, they have prepared for months for their chance at the helm and they start the job with unlimited energy. They have often agreed with family and friends that it is time to clear the decks for this once-in-a-lifetime opportunity—the job will take precedence. In the first 12 to 18 months this works fine and they are truly unstoppable. All around them express amazement. Over time, however, cracks appear. Many repeat CEOs will tell you they ignored their personal sustainability at their peril and they approached their second and third chances with more humility. They developed more self-awareness that they were not superhuman and understood that a sustainability plan was necessary not only for themselves, but for their companies.

3. Legacy matters: The consideration of your legacy is not, in our view, a negative. Instead, it is a lens that can help you make the right long-term decisions for your firm. The best CEOs consider their legacy deeply as they consider how to be the best leader. It forces them to ask and answer: Will the leadership team I leave be better than the one I inherited? Will the talent we want be more likely to join the company after I leave the job than when I started it? Have I created a more loyal customer base? Have I nurtured core capabilities, leaving a strong foundation for my successor? Have we done right by our communities? These are "true north" questions that help CEOs navigate through all the more urgent, but often less important, issues that fill their agenda—how do I hit this month's profit target, how do I respond to this week's people crisis, and so on.