Each player starts the game with only 10 cards (the Starter Set), taking 5 cards to their hand each turn. Whenever a turn is finished, you can choose to keep or discard the remaining hand cards and up to 5 new cards are drawn. So after 2 turns, the deck is potentially empty. Thus, the Discard Pile is shuffled and becomes the Draw Pile again. The deck is played over and over again.