I am of the mind that it's a machine and if IT only worked correctly with a "name brand" thread, that info would be in bold letters in the manual and stamped on the bobbin! I am suspicious of a dealer recommending a certain thread...especially since they are a dealer for that product. Cha-Ching .......I have sown for many years using old, cheap, expensive sewing machines and have used old, new, thin, thick threads on all and they have worked fine.....so my conclusion is...the operator knowing, not IT telling....JMHO