Because consulting is the gift of perspective, a consultant can only be effective for a limited period of time, i.e., the time they are able to maintain authenticity and continue to offer an independent perspective about the organization and its problems.
At some point, however, the consultant loses the gift of independent perspective and develops tunnel vision. This can happen in one of two scenarios:
In both these scenarios, the organization may still keep the consultant around. In fact, the average organization is much more welcoming toward a consultant who’s reached their expiration date, because they’re less threatening (they’re seen as “one of us.”)
The good consultant understands when they’ve reached their expiration date and gracefully makes their exit.