Sorry I didn't ask this with my first post regarding quilting needles, but what size needle is preferred when sewing on the sewing machine? Is it different for piecing than with quilting?

it is whatever size fits in your hand and is comfortable.
some use betweens (quilting) while others may use sharps.

I use a 14 usually, but some will use down to a size 12.

I usually use a 14 or 12.

For machine piecing I usually use a 10 and for machine quilting usually a 12.

I use an 11 or 12 for piecing & a 14 or 16 for quilting at the domestic machine. I use a 16 or 18 on the quilting machine. The size needle you use is determined by how thick your thread is.

For 28 years I've used a Schmetz Universal 80/12 for most machine piecing.

Jan in VA

I checked my book on machine & used what they suggest for quilting.