I use Prescencia 60/3 thread on cones for piecing and for quilting. 60 wt. thread is finer than 50 wt, but since it is 3-ply, it is just as strong. I purchased black, white, grey and two shades of beige three years ago for $25 a cone. I was taking a class from Harriet Hargrave and she said it would seem like it lasts forever, and it does. I only use spools of thread when I'm doing topstitching or machine stitching a bindng and want to match the fabric.