Why institutional memory matters.
A school's knowledge shouldn't walk out the door when a person does.
When a Lead Guide leaves, they take with them years of accumulated understanding: which materials need attention, how this classroom differs from the catalogue, what commitments were made and why. If that knowledge is in their head, and only their head, it simply disappears.
The children who come next year deserve the same quality of environment as the children who came before. That requires a record that outlasts any one person.