Want to retire early? People who have done so already say to focus on 3 expenses Maskot/Getty Images/Maskot Business Insider has spoken with dozens of early retirees. Rather than focus on cutting back on small things, like coffee, they focus on 'the big three.' Trimming housing, transportation, and food costs could transform your finances. If you're trying to retire early, reach financial independence, or simply improve your finances, start by taking a close look at three expenses: housing, transportation, and food. Often called "the big three," these categories are typically among the largest expenses most households face. Many early retirees say they focused on reducing those costs rather than obsessing over smaller purchases, like coffee or streaming subscriptions. "If you learn how to master those big expenses, it will free up a ton of money so you don't have to stress about the small stuff," Josh Lupo, who retired in his 30s with his wife, Ali, told Business Insider.…