There isn't a fixed number of turns required to win Splendor as gameplay can vary based on player choices and interactions with opponents. However, typically one should expect anywhere from 15 to 20 turns for a game to reach completion, depending on various factors such as player experience, efficiency of strategies implemented, and how quickly players acquire development cards or satisfy noble requirements. It's important not to solely focus on turn count but rather adapt your strategy throughout the course of the game based on emerging opportunities and challenges presented by other players' actions.