I prefer not to piece my borders, but if I did not buy enough fabric or if the pattern is going the wrong way, I piece. I I have put a different piece of fabric in the middle of the sides and for the cornerstones, I have made piano keys borders where I sew a bunch of strips together and cut them to the desired length, I have pieced strips of different fabrics together. If it is going into a quilt show I try to either do one piece borders or borders that are intentionally pieced. I once entered a quilt in a show and I had used a striped fabric in the border ( and to get the affect I had to cut it crosswise). I oh so carefully matched the joinings -- they were as good as they could be. The judge said that one should never piece a border unless it is meant to be seen as a pieced borders -- if all the same fabric is used it should be a whole strip. (She was a lot less polite -- said something about lowering the quality of the show,, too). Got to love the quilt police.