Originally Posted by PaperPrincess

Jennifer beat me to it! If you combine a charm square with a pieced unit made up of other charm squares, like half square triangles, 4 patches, etc, you will need to cut the full ones down to match the size of the pieced units. The pieced units will be smaller because of the seam allowance. It all depends on the pattern if you need to trim them to a smaller size or not and what that new size will be. I really don't think it has anything to do with pinked edges.