I think about credit cards all the time. As a personal finance journalist, I've written about credit card rewards for a decade now, and have more than three dozen active cards of my own.

One of the tried-and-true budgeting methods is known as the 50/30/20 rule: budget 50% for your needs (rent, utilities, and groceries ), 30% for wants (going out to eat and hobbies), and the final 20% ...