The polyester thread will not shrink as much as cotton thread, so if you are looking for that old-timey puckered look after washing, you might not get the desired look. If you don't care, or you don't plan to wash the completed piece (maybe it is a wall hanging), it shouldn't matter. I have used Gutermann for all kinds of projects, preferring to save it for crafting projects (pin cushions, jewelry pouches, so on) and use the better mostly cotton threads for quilting.