Starting as a newly appointed leader in an organization is akin to getting hit by a tsunami. Meetings, presentations, crises: all requiring time and energy from the new executive. The “tribe” will show patience and tolerance—up to a point. From our collective experience, that point is about 90 days. That’s how long the new leader has to gain traction before the tribe starts to lose confidence.

All of this makes it essential to take control of the agenda and be rigorous during that critical start-up period in making investments of time. The first thing to understand is that there will never be enough of it. Even if the new leader logs an extraordinary number of hours per day including weekends to master the new role, he or she will be unable to accomplish everything on the ever-growing to-do list. This is precisely why they need to make the proper calls on where they will invest those precious hours and where they will pull back.

Let’s start with the important period before Day One. I have seen over and over the tremendous benefits that accrue when newly appointed senior leaders invest time before assuming the role to gain a deeper understanding of the business. By investing time upfront, they can form a view of the challenges to come while building relevant knowledge. This investment allows them to develop working assumptions about the business, team, culture and stakeholders before they join. This way, new leaders can start validating their working assumptions from Day One rather than having to construct them on the job. In essence, investing time upfront means getting time back that can be invested in other areas once they start in the role.

One newly appointed CEO at a €500 million B-to-B listed business who had been hired away from a competitor was able to engage with the board early on. This gave him an important opportunity to delay a specific acquisition before he took office. That delay proved to be critical. Once he assumed the role, the new CEO presented a post mortem for the board of the company’s acquisitions over the previous seven years including the return on investment, which was far weaker than understood. The revelation led the board to halt the acquisition that had been under consideration—and all other M&A activity until the CEO could review the situation.

Equally critical is how the newly appointed leader invests his or her time in the first months, once they join the new organization. When the new leader has sized up the challenge properly, he or she have a full picture of the integration challenges and will have developed specific actions for addressing them as part of their 90-day plan. The plan should be both strategic and operational, stipulating exactly how time will be invested in various areas as well as outlining a number of specific learning and briefing activities, such as meeting with core customers, stakeholders, partners, visiting key countries, and attending internal meetings. The plan should be carefully designed and intense in its pace. Correct sequencing of events is also critical, not only in terms of leveraging the events themselves to minimize the time required to gain full effectiveness, but also in terms of signalling the right messages to all constituents.

Very often at the n-1 and n-2 levels, newly appointed leaders struggle to follow their integration plan. In reality what happens is that these leaders are joining a business that is already running: things are happening and people are continuing to play their roles. The leader gets pulled into routine meetings that have already been scheduled or new meetings that they are asked to join for all the right reasons. The cumulative effect: the integration plan slowly loses altitude.

Leaders themselves need to keep careful track of where their time is going. I strongly advise new leaders to proactively balance their time between the activities that proactively address their integration challenges and are part of their integration plans with the time invested on reactive, ongoing commitments that come with the role. While the second offers them valuable opportunities to learn on the fly, it is essential that they don’t sacrifice the first. If that happens, the first 90 days will go by very fast and leaders will miss opportunities to properly integrate and accelerate their progress behind their integration-plan activities.

The tribe expects their new leader to learn, engage, and assess. But not forever. If the leader is still missing key pieces of knowledge and insight after 90 days, the Cliff Effect kicks in. Thus, new leaders need to take control of their time and invest it where it will have the most impact. To ensure this happens, they need to align with their stakeholders, including their team, and communicate exactly what they are doing and why they are doing it. No one can do it all. The trick is to do that which is most important.