The current scenario shows the rise of mobile games. With low entry barriers for both developers and players combined with the advantage of having the game on-the-go make cellphones a strong competitor as a game console. With time related game mechanics, the IDLE genre has an advantage over others, fitting the needs of the player that can t be on their phones over long periods of time. With those said this study has as its objective, analyze the monetization and play retention on five successful mobile idle games in order to find if there is a common practice among them and help future developers and contribute to a formal literature over the topic. The study results concluded that monetization is at a more mature state than player retention. Among the studied games, all of them presented in-app purchases and 4 out of 5 presented ads, presenting a strategy of mixing those two practices. By the other hand retention practices seem to be more dependent on the game itself, varying too much among the games analyzed.