I charge everything throughout the month, including my vacation, and then pay it off at the end of the month. Okay, with the vacation, I'll pay it off within the six months of free interest.
But I earn cash back on each transaction. That's why I do it. Never charge more than we can afford, but why not take advantage of that? Even if it's only 1%, it's better than nothing. It's one more souvenir I don't have to pay for!