Here is where my exuberant notching pays off. It's way too easy to sew pieces together backwards or to the wrong piece. Since I've notched the pieces all I have to do is match up the notches. Also since I shape my seam allowances it makes it easy to line the pieces up by matching the end points.
Back pieces have two notches, there is no way one of them can accidentally be fit against a front piece. What piece do those connect to after they are sewn? Match their seam line to a notch on another piece and there you go. Maybe the piece at the side where the boning will be does not need a notch at every seam junction, just one at the front waist and two at the back will do. But sometimes it's difficult to tell the face of the fabric from the reverse. It blows to have to pick a seam out because I've flipped the material. Those notches give me an easy way to double check that I have it right. One could argue that the center front and back pieces don't need all those notches showing where the cross seams hit, just one at the center front and two on the center back would suffice. But with those notches there is no way to sew the back piece to the front, or flip the piece and sew it upside down. Years from now I can sew up this pattern without wondering how the pieces fit, all the information is there in the notches.