The advantages of only playing premium hands in the early stages are not only _"avoiding mixing it up"_ but while you're folding so many hands, you're also getting time to get good reads on who you're up against. And your folds are giving the other players the image that you're a very tight player. So later, when there are fewer opponents left and you're closer to the money, you can expand your range and bluff more because any raise is going to make your opponents think the tight player is holding a monster.
