In a game of blackjack that uses multiple decks, players should adjust their strategies due to the alterations in odds and card distribution. With more decks in play, the impact of card counting becomes less effective, as the player has to track a wider range of cards, making it harder to predict the composition of the remaining deck. Consequently, players may want to rely less on card counting and focus more on basic strategy, which emphasizes optimal decisions based on their hand and the dealer's upcard.