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 typica