Aurifil Forever!
When I purchased a new sewing machine about ten years ago, I asked the sales clerk what brand of thread she recommended using with it. I had done very little sewing for about forty years, and I figured my collection of old spools was too old to be any good. The first word out of her mouth: Aurifil. I purchased my first spool of Aurifil and have not been disappointed. It works great with my ten year old Pfaff and my 74 year old Featherweight. I’ll never use anything else!