Ball Point needles were designed to be used on knit fabrics. If you are piecing with a non-knitted cotton, I would recommend you use a different needle. I have seen people who will not change a needle until it breaks, or becomes so bent that it cannot be used. Needles are one of the most important parts of piecing quilt, and I want to get the best result I can........so I change my needles after about 8 hours of sewing - 3-4 hours of embroidery work. You can buy good universal needles in bulk ( I got 100 for about $35.00 from my Viking Dealer).....Hope this helps.