For piecing and if its on my regular machine and especially if it has lots of seams and finished size counts, I always use Aurifil. Love it and its low lint and strong, its two ply instead of 3 and really helped me get my small civil war blocks to come out accurate. If its on my serger then I use serger thread and never have to worry about filling a bobbin so that works out great. If I want to make sure a quilt holds up I use the rule of cotton fabric with cotton thread, over time it won't break down the fabric. I know some don't think this is true and that's ok, I was taught this from an expert who has been around along time and is award winning so I go by what she taught and don't discriminate anyone who uses other threads. To each his/her own I think