Schmetz, no question. I piece with 70/10 sharps and quilt with 75/11, 80/12 or 90/14, depending on the thread. I change them often, at least every project and sometimes halfway through if I'm using poly batting or batiks which wear the needle more quickly. An old needle can strain the motor on your machine and a new needle is a darn sight cheaper than a new machine. :-D