The implications of this kind of leap to a company’s economic model can be devastating. In IBM’s case it meant the collapse of gross profit margins and the attendant changes we had to engineer to lower our cost structure without compromising our effectiveness.

Yet the hardest part of these decisions was neither the technological nor economic transformations required. It was changing the culture—the mindset and instincts of hundreds of thousands of people who had grown up in an undeniably successful company, but one that had for decades been immune to normal competitive and economic forces.

Even though it’s crucial for a new leader to show that he or she fits into the culture and “gets” it, the paradox is that you don’t want to settle in too comfortably if the culture needs modification. But of course, changing a culture is never as simple as ordering it to be so, especially if the organization is very proud of its traditions. And what organization isn’t?

As Lou Gerstner says, “Changing the attitude and behavior of hundreds of thousands of people is very, very hard to accomplish. You can’t simply give a couple of speeches or write a new credo for the company and declare that the new culture has taken hold. You can’t mandate it, can’t engineer it.

“What you can do is create the conditions for transformation. You can provide incentives. You can define the marketplace realities and goals. But at some point you have to trust. In fact, in the end, management doesn’t change culture. Management invites the workforce itself to change the culture.

Creating the conditions for a cultural transformation takes all the tools at your disposal. You can’t, for example, command an internally focused culture to magically metamorphose into one that canonizes its customers. You have to nudge, suggest, cajole, and ultimately convince people that the new environment you’re proposing really is the best one for the business and, perhaps more important, for themselves. That takes time - and a good sense of timing.

Some leaders look back on their first hundred days and say, “If I could do it again, I wouldn’t hesitate so long to make those key people changes or that strategic move.” Others were glad they exercised restraint. In most cases the timing are dependent on the situation.

Just remember that too much change can break the culture - or more likely destroy the change-maker. You have to pace yourself and continually assess the tolerance of the organization.