Over the past few years, I have seen an increase in the number of quilters choosing to press their seams open rather than to one side. I have heard several reasons for this, including long-arm quilters having trouble with thread breaking when stitching over bulky seam allowances, the quilt/wall hanging lays flatter, especially when working with very small pieces that have a significant amount of seam allowances relative to the front of the piece, and some machines stitch better over the seam allowance without shifting the fabrics.
Since I have the opportunity to sew on a wide variety of machines, including long-arm machines, I can understand some of the thinking behind these reasons. However, I have reservations in choosing open seams over seams pressed to one side for every project. When I think of the construction of the seam when seams are open, the top of the quilt at the seam is only the stitches of the seam. If, for some reason, the tension on the machine is not set well, the integrity of the seam is going to be compromised. I know that in my earlier years I did not know enough about tension to really concern myself with it and many of my projects were not as good as they could have been because of this. Even now, I come across a machine every now and then that I can not get the tension set because it is that old or of a lower quality. This is frustrating, but, when seams are pressed to one side, the issue of poor tension is minimized. I have had some people in class that were told by another teacher to use very small stitch lengths to counter the fact that the top will only be the stitches. The subject came up when I was offering to rip stitches for them. They were grateful to have my help and I then knew why!
The main reason that I like seams pressed to one side is that I can lock the seams. This makes my sewing so much easier and I do not have to pin. If I am working with a machine that seems to push the top layer, I lessen the pressure on the presser foot and that usually allows the fabrics to go through easily. As for the bulky seams, I would recommend using a tailor’s trick to hammer the area; that is how they deal with thick seams, such as when making a wool coat with bulky seams at the shoulder or pockets. I have found that sufficient to tame the fabric so the thread does not break when quilting through the layers.
Send us your reasons that you like pressing to one side or open. I am sure there are more reasons out there based on individual experience and circumstances.