My stitch length varies with the quilt. I like to press seams open (former seamstress here), so I keep my stitches short. My default is 2.5, but I will often use 1.8 for piecing. When I was less experienced, I kept the default at 2.5 and learned how to press my seams to the side. That way if I had to rip out a seam, it wasn't such a horror. I must say that my Gingher seam ripper made me more willing to use smaller stitches because it can handle those smaller stitches more easily. Also, if I'm working on thinner fabrics, I'll use a shorter stitch, whereas if the fabric is thicker, I tend to lengthen my stitch, but not over 2.5. I do go longer (3.0) for FMQ.