Well it does that on two days of the year, that is at the equinoxes.
And your latitude.
Not only do you need to know how how accurate you need to be, but you need to know how accurate are your approximations, and where and when they can be used. The wrist watch method and the sunrise/sunset directions are approximations, and much of the time not good ones. There are parts of the world where at times they are of no use at all. In the arctic circles, at some times of the year the sun neither rises nor sets. Either it just goes around you all day, or you don't see it at all. In the tropics, the midday sun never strays far from overhead. Inbetween the tropics and the arctic circles, things can get intersting. It's all in the book.