If the cards are damaged or marked during play the deck is punched and disposed of. After a certain small number of uses, where normal card handling by dealer or players might mark there cards, there deck is punched and disposed of. I would be surprised if a big Vegas casino does not go through a shipping container of card decks every night.
Shipping containers are pretty big compared to a deck of cards, even a 20-footer. Looks like an average casino goes through on the order of 1,000 decks of cards a night.
