this is the same thing that I read this morning from Colitiers. if you use poly on cotton it will end up cutting thru the fabric. they say you should match the type of thread w/the type of fabric; use cotton w/cotton, and so forth. for quilting, especially when the 1/4 in is important I use auraphil (I'm sure I spelled it wrong) it's makes alot of difference and I never have a problem with it breaking. If the 1/4 in isn't as important and the item is made from a lesser quality of fabric or flannel then I use up what ever the thread is that I have on hand before I found out about aurophil. I want most of the things to last for my kids so I use a good quality thread for that. All of the shops around here recommend this thread and so does Viking for the Mega Quilter.