I love your question! There are no quilt virgin projects in this sewing room.
All the fabrics are from the LQS or on-line orders and rarely from the big J store. There is a separate stash of home-dec fabrics keeping me company for curtains, pillows, etc. I don't mix the two fabrics though.
I piece with embroidery thread often and use it for bobbins too. Right now, I'm using up bobbins with embroidery thread to get some empties back in the bobbin box. Love piecing with pre-wound bobbins as there is so much thread on them. My other favorite is glide thread used for piecing, bobbins, and quilting. I don't like cotton threads as they are linty in my machines and seldom use them.
Happy to say that I've never had any quilt instructors with purist thoughts. LOL!