Originally Posted by littlehud
I can tell by the way my machine sounds. There is this faint thunking noise and then I know to change the needle. My kids can't hear it but I can.
Ditto. The sound changes. I was in a class at Viking, and the instructor/owner called out a student for having a dull needle. She could hear it across the room. Also, if not sewing right, and nothing else works, change your needle right after you try rethreading.