For a critical role with a foreseeable departure, I would aim to start around two years ahead. The right lead time depends on how long it takes someone to learn the work, build the relationships and demonstrate they can make the difficult decisions. Keep an emergency cover plan in place even when no departure is expected.

Work back from the first decision the successor must make alone

Think of a small investment business where one person knows why certain controls were put in place, which service provider issues keep coming back and how the board expects to hear about them. You can document much of that. The harder part is teaching someone to distinguish a routine problem from one that needs intervention.

In one small team I know well, planned handovers are worked around the business calendar. Starting two years out gives a successor the chance to see two year ends and several interim cycles. The first time, they can see how the incumbent handles the awkward calls. The second time, they can take the lead while the incumbent is still available to challenge their judgement. That is a much better test than attending a series of handover meetings.

Give internal candidates real opportunities to prove readiness

If you have someone in mind, tell them what they need to show and give them work that allows them to show it. That might mean owning an issue with a service provider, taking a paper to the board or leading a discussion when two stakeholders disagree. Agree who will coach them, who will assess their progress and when you will decide whether the plan is on track.

It is also worth understanding what the external market looks like before you need it. A discreet look at the talent pool can help you judge whether to build capability internally, hire a deputy with room to grow or run an external search. Give internal candidates honest feedback and avoid implying a promotion has already been decided.

Plan for a surprise as well as a handover

Write down who would take immediate responsibility if the incumbent left suddenly, what that person could decide, and where they would need support. For regulated roles, involve your compliance and governance colleagues early. Where a successor would perform a Pre-Approval Controlled Function (PCF), use the Central Bank of Ireland’s Fitness and Probity guidance to check what approval and due diligence steps apply before appointment. Work those steps into the plan alongside development, recruitment and notice periods.

A good place to start at your next leadership meeting: pick one role and ask “What would be hardest to replace if this person left?” The answer will tell you whether to start by sharing knowledge, developing a deputy, checking the market or doing all three.

If that question brings a particular role to mind, I’m happy to talk it through in confidence. We can start with what the business would need to cover tomorrow and what a successor could start learning now.