Kitsie

Mostly #1, but occasionally #3.

grannie cheechee

I use pre wound bobbins. I use light colors on top if piecing light colored fabric, and dark thread if dark colored fabric. I let my quilter choose the colors when she quilts my tops.

NZquilter

I just use the same thread on the top as in the bobbin, usually a white or off white for everything, even quilting. I don't really know why, so I'll say probably "just because!"

Becky's Crafts

I coordinate my thread colors with the fabrics I'm using. My usual weight thread is either 40 or 50 weight. Sometimes I get really creative and work with the variegated threads on my quilt top while quilting. The bottom thread usually matches the bottom fabric.

joe'smom

I'll use a different color bobbin thread when piecing if I have a partial bobbin to use up.

When quilting, I always use the same thread top and bottom because pokies show if I use a different color.

WoolinRougeDesigns

It depends on the project for sure

Mitty

I use the same type/weight of thread for the bobbin as on top. The reason for that is just that it has worked for me and then I don't have to buy as many different types of thread.

Whether I use the same color depends on the situation. For things where the thread won't show, I often use up old bobbins and they usually don't match. For quilting, I'm usually trying to blend into the fabric, which frequently means using different colors on top and bottom.

judykay

I do all three ways depending what is wound on my bobbin. Never have any problems using different threads.

Onebyone

I use different threads for piecing. But I use a thin thread in the bobbin no matter what type I use on the top.

Sandra in Minnesota

Usually #1.