Know the rules, then use them fast: Balances last 5 years; inactivity fees after 12 months; some states cash out small leftovers (e.g., CA $10) Buy low, sell smart: Warehouse clubs = easy 20% off; ...

With over a dozen credit cards and millions of credit card points racked up, Nancy Jiang condenses the complex world of card-churning for maximum rewards with minimum effort. Her work has been ...