I have been doing the service on my big machine since we got it in 1961. My DH did put the new motor on for me tho.
On my Featherweight, I was so scared I took it to a repairman who a friend had used for a long time. He showed me what to do, why and what not to do; like take the bobbin apart. After one time I have been doing this one by myself. Think it is a matter of confidence and feeling you won't 'mess it up' too badly!
Mariah

Yes Mariah, I think confidence is a big part of it, and also being willing to go through the hassle. Since I don't have any newer machines, the repair man will be there for me on days when I just don't have the time or patience for it.