Last spring Brett Favre pulled the plug on his pro football career, saying that he didn’t have the heart to play any longer. This July he's had a change of heart. This is not the first time Favre has changed his mind about retirement. But what's different this time is that his team, the Green Bay Packers, don't want him back.

For the Packers organization, the saga is bigger than just one player, Favre. It's a succession planning story. Succession planning is not about individuals leaving; it's about organizations preparing for the future. Effective leaders eventually will need to be replaced. And so Favre’s “un- retirement” raises questions about when a leader should leave and why. Here are some questions for the organization to consider:

What does the leader contribute to the organization? Good leaders who have led for a long time have a presence that is tangible but not necessarily measurable. Organizations value them not because of what they do but because of their ability to mobilize others to action. Removing that person from the organization will create a leadership vacuum in terms of authority, initiative and presence. Organizations need to understand the effect that their leaders have.

Who can replace the leader? Good leaders are hard to replace, but too many organizations make the mistake of trying to fit an exact replica into the slot. Successful organizations find the right person for the job, not the person that most closely resembles the previous leader. You're not finding someone to lead yesterday’s team; you're hiring someone to lead tomorrow’s team. That may require a completely different set of talents and skills.

How can the organization prepare the incoming leader? The organization needs to think about what it needs its leader to do and help her achieve it. For example, if the organization needs to focus on execution, it needs to be willing to invest in operational aspects of the business. On the other hand, if growth is a priority, investments in product development and marketing are essential. However, these directions must be jointly decided. So often new leaders fail because their goals do not match organization goals; synchronicity is essential to success.

Without question, Favre was the most exciting quarterback of his generation; his gift for spontaneity made him a play maker who could tangle a defense in knots and help his team score. But when he retired, the Packers planned for his absence by grooming a successor and installing a new offense. The team had already executed on its succession plan.

Even with great leaders, it seems, it's not what you have done in the past that matters most; it's what you will do in the present and future that makes a difference.