The As Occupied state captures a building after tenants and operators actually move in and start changing things - rearranging partitions, adding equipment, modifying finishes - changes that happen entirely outside the original project team's control or awareness. Keeping an As Occupied record current is genuinely hard, which is exactly why it matters: an AIM that was accurate on handover day slowly drifts from reality as occupants make their own changes, and a facilities team working from a stale model is planning maintenance and renovations against a building that no longer quite exists.