One of my first classes taught us to stay-stitch borders and quilts.
I always stay-stitch borders and quilt edges using a 2.0 length. Then press the edges again and sew together. I also pin at half-way points and then at 4 or 5 inch segments along the border. It doesn't add much time or effort to the project. I also square up corners after adding borders if needed.
For me stay-stitching locks down the fabric and prevents possible stretching. Generally quilts are within a 1/4 inch when ready to quilt.
It's not for everyone, but it works for me.