I press all my seams open, and have never had a problem with wear and tear. Of course, I use a very short stitch while piecing, and I'm careful to press the seam closed (to bury the stitch), and then press them open. When doing stitch-in-the-ditch, I will also fortify with a stitch on one or the other side, or both, or some echo stitching. Just my way. A little extra quilting and pinning is worth it to me to have my points line up. To each her/his own!