When we crossed the border, the exchange rate was $1.13 to $1. Now it is $1.25 to $1. Many of the charges we have made are showing up three to seven days later - we are getting a better exchange rate with the delay. This benefits us as long as the US dollar is rising. If the US dollar begins to fall, getting a chunk of Canadian cash will save us money. As it is, our money is 'growing' with us not doing a thing.
(Our credit card charges us 1% on some purchases as a separate line item. Otherwise, the charge matches the rate of the day the charge posted rather than the rate of the day the charge was made.)