I facilitated a session a few weeks ago where some participants talked about the need to replace the "old guard" with some new faces and fresh thinking.
It's a common concern and a common expression. No doubt for even the most dedicated of lifelong learners there is an expiration date on the value of their tenure in a particular role.
But remember, just because you're changing the guard doesn't mean you necessarily want to change what they were guarding.
People and programs will come and go.
Purpose should be more permanent.