Why wartime maintenance schedules collapse

How severely do modern naval maintenance schedules deteriorate during wartime?

They can deteriorate quickly because casualties and force requirements push otherwise scheduled ships back into service.

Maintenance remains schedulable in theory, but operational requirements decide whether a ship can actually enter dock. A planned deep refit depends on another unit being available to cover the same fleet task. If that equivalent ship is damaged, the force still has to maintain the required number on station. The available ship's dock time is then deferred, and the maintenance backlog begins to compound.