Agree with above, most threads are good quality. However I have some old thread from my Aunt which before I put them in my sewing room I pulled on them. If they broke real easily I threw them away. If they held their tug like the new ones I kept. some of those threads (over 40yrs old) I"ve used in my grandchildren quilts and believe my after 40 or more washing's, they are still holding up.