I have never used a compass in a vehicle, but have a pretty innate sense of cardinal direction at all times. Maps, however are a must. We do have a GPS, but find it most valuable when in a strange town or city and looking for stores and restaurants. I've never liked blindly following "turn right, turn left" directions without having a larger picture of where I am and where I'm heading. Nothing on a 5 inch screen can replace a good map. Of course, you must pull over and stop before reading a map.
Now, when going out into the woods on foot with no trail (bushwacking) that compass is a must. Especially in areas with little topography where you can't pick out landmarks. As a forester, I've gotten "a might bewildered" a couple of times even with a compass and an aerial photo.
