I know this might be a hot topic, but still, it bears discussion.
I asked this question at MQR as the question of the week, but I think I'll repeat it here.
How do you press your seams? to the side, or open? And why?
All I can say is, there is no right or wrong way...only the way that works for you.
I am going to talk about what works for me.
I press open. OMG! Did she really say that?...yes I did. And here is why.
Yes, I got a nice 'nesting' when I would press to the side as I was taught "a thousand years ago, lol" .
BUT! and this is a big but: If I have more than two seams that come together, it really can throw my accuracy off....both at the piecing stage and at the quilting stage, with that telltale lump.
As a former" longarm quilter for hire" I can tell you that I quilted my share (and then some) of lumpy quilts. You know what I mean...those huge lumps at the seam intersections.
Well, after a few of those, I started looking at my own piecing/pressing habits. They were straight out of the quilters bible..".press to the dark side" unless there is too much bulk...then press to the light side.
That works fine if; and it's a BIG if: #1 there are only two seams (or maybe four); and #2 the fabrics are either; of equal value so there is no show through when pressing to the light...and you are fastidious about clipping any overhang and ALL your dark threads.
Neither of which seamed to work in my business life.
So, I wanted my quilts to be better...I compete, so that is important. So I started pressing all my seams open.
Now I don't make a lot of pieced quilts, but I do make pieced backgrounds for applique. And, I want to 'grow' as a quilter and artist.
So, I tried pressing the seams open. At first, only the ones where many seams came together...I was waiting for the quilt police to come....they never did. AND, I liked how nice and flat my seams were.
So I tried it on others, and I have to tell you...I am a convert to pressing everything open.
And the benefit...other than less lumps when I go to quilt a piece? WOW, I find that I am soooooo much more accurate!
Now, a perfect piecer, I will never be. But I am pleased with how much better my piecing is. Now, in full disclosure, I also starch the snot out of it all at every step of the way. (Only good for pieces you can wash). But mostly what I do other than wholecloths, is appliqué...and I use a h2o soluble stabilizer and glue for that...so washing is a given. The exception is the art quilts I do with mixed media...those don't get washed (just vacuumed) so no glue or starch on them.
But for washable quilts, press it all open is my mantra. Some examples....Notice I use two colors of thread...one that blend with each fabric...there is nothing more distracting than seeing contrasting thread in a seam



I really like Mary Ellen's Best press, but I ran out...this worked fine



look how nice they went together


No, I do't proclaim to be a perfect piecer...nothing could be further from the truth, but I do want try keep trying to improve my techniques, and this has definitely helped. These blocks are not perfect by any means, but they are pretty good. And even though pressing open takes a couple seconds longer...I'm OK with that. I've never been a fast quilter anyway...either at the piecing/appliqué stage, or at the quilting. My view...slow and steady wins the race. And makes me happier with the results.

and look, that backs are as pretty as the fronts!

So is this for everyone? No, probably not. But it works for me and I am very happy with my blocks.
now, as to that question I know you're asking...What about stitching in the ditch on all those seams that are pressed open? Well, in my own quilts...I quilt it all to death...so I am adding thread on top of thread...I think it will all hold together :)
Not for the faint of heart, I know. But...........