I use 2.5 for piecing (the default on my Brother and Pfaff), and bump it up to 3.0 for quilting.

My Elna 7200 automatically sets up for 2.5 which is fine for piecing, I bump it down to 2.0 or just below for PP and when doing my binding etc. I bump it up to at least 3.5 or above depending on the wadding loft.

Hmmm... normally it depends on how fast I move the fabric for free motion. If I use my walking foot I set it to 3.0 or 3.5 for hatching. If you mean piecing I like 2.2 but I might set it slightly larger but not more then 2.8 for piecing. I set it larger just incase I need to take it out. 2.2 is just too small for me to take it out.

I use 1.8 for PP, 2.0 for regular piecing, 3 or 3.5 for quilting using my walking foot.accufeed.

Janome 6600 comes set at 2.2, but for piecing I bump it up to 2.8. I think 3.5 is big enough that rings, etc may get caught in it.

For piecing its 2.0 or 2.5 for the actual quilting its 2.5 to 3.0. rarely its larger to a 3.5 if I am using a larger or much thicker thread.

I have a Bernina, I piece at 2.5 and quilt at 3

I piece at 2.5 and quilt at 3 on all my machines

My Sapphire 875Q defaults on 2.5 - the stitches are too far apart for piecing so I bump it down to 2.0 - I think it depends on the machine - I really don't know what the 2.5 or 2.0 indicates other than one is bigger or smaller than the other - does anyone know what they even mean?

For piecing, I generally use 1.8. If sewing on the bias, I shorten the stitch to about 1.5. For quilting, it's around 2.2.