If you prefer the convenience of plastic, use debit cards for everyday purchases like meals, groceries, and gas (just don’t spend more than what’s in your bank account). Avoid using credit cards for these small expenses or you’ll wind up paying off those debts long after you purchased them (and paying more for them with interest rates). Reserve credit cards for big-ticket purchases like furniture and airfare that are easier to remember. If you find yourself reaching for your credit cards between paychecks, you’re probably living outside of your means and it’s time you cut unnecessary expenses.