I was having a discussion with some one the other day (while riding with them) and they don't use their F'ing cruise control while on the highway. IMO using your cruise control is one of the best ways to get good fuel economy. Studies have shown that you can get up to a 14% improvement by using your cruise control. Moral of the story, if you have it, USE IT. Note that if you are driving in mountainous country CC is not a good idea. With even the cheapest Silverado (the W/T) coming standard with CC, there's no reason not to use it.