I have an early featherweight, 1936. At that time, they did not make the numbered tension knob, so if I change a tension there is no reference to change it back. It takes some fiddling sometimes compared with later models that have the numbered tension knob. She sews fine though! You are right, it is mostly a matter of personal preference. I love that my machine is twenty years older than me and still going strong! I enjoy imagining the different folks who must have used her over the years.