It may seem strange to think about succession on your direct report’s first day but there may be no better time. In this case, I’m talking about the part of succession that makes certain you have the critical aspects of your direct report’s job functions documented sufficiently enough for someone else to be able to know HOW to do that aspect of the job.
From the first day your new hire, as a matter of survival, will be carefully documenting how to perform their job duties for their own use so that steps are not missed and repetitive questions can be avoided. After your direct report has successfully completed these functions based on their own notes, simply take those notes and formalize them into a succession plan for the job.
This documentation can then be used for cross-training and development purposes of co-workers who may be groomed for performing those very tasks at a later date. You also communicate to the new direct report, that you anticipate their continued growth in the organization; preparing for someone at a later date to perform those tasks will allow for time and opportunity to learn new tasks of their own.
If you wait until someone is well ensconced in a role, the detail with which they document tasks may not be of sufficient detail to allow others to complete the tasks without personal observation or some trial and error.
Empower your direct reports for their own development by ensuring the documentation of critical tasks which may be done by others in (or outside of) your organization.