Any time I have ever taken a class on thread, the instructors have said to NEVER used Coats & Clark or Dual Duty thread. Of course after hearing that I went home and looked through threads and as you can guess, I'd been using Coats & Clark for everything. I made the switch to better thread (my favorite is Aurofil!!!!!!!) & was amazed at how much better & easier it was to piece/quilt. I'd definitely recommend using good thread & save the cheaper stuff for things like basting. JMO.