Cycle counting checks a small part of the inventory each day or week, a zone, a category or a list of items, so that over a cycle every item is counted. It replaces or reduces the annual wall-to-wall count that stops the warehouse.
Counting often also catches problems while they are small: a mis-pick, a damaged case written off on paper but not in the system, a lot put away in the wrong zone. The variance between the count and the system tells you where the process leaks.
In APFoodz counts are scanned on the floor and the differences flow through to the books.