I have had my APQS longarm for over 20 years, and have had very few problems with tension. I use prewound bobbins and MaxiLock thread. I have not had problems with Superior prewound bobbins, but I tried some more expensive threads such as Superior, and my machine did not like them (thread broke many times while quilting a quilt). I never mess with my tension. I have been very happy with my machine.