When card counting, the number of decks you aim for depends on the game and its rules. Single-deck games are easier for beginners because there are fewer cards to track, giving counters a clearer advantage. Double-deck games are slightly more challenging but still manageable. In multi-deck games, such as those with 4-8 decks, it becomes more difficult to maintain an accurate count, so counters use the "true count," which adjusts the running count by the number of decks left. While multi-deck games are harder to count, experienced players can still gain an advantage with practice. However, casinos use more decks specifically to reduce the effectiveness of card counting.