Originally Posted by irishrose
Modern machines need to be cleaned professionally once every year.
I disagree. First, a lot depends on the usage in a given year so a calendar period can't be used, a better measurement would be hours of usage.
That said, when I was bringing my machine (Huskvarna) in once a year my service man asked me "why? It honestly doesn't need it". He could have easily continued to let me bring it in once a year and billed me for it. I keep my machine very clean - bobbin area, needle shaft, feed dogs, and any other area I can reach is cleaned at least with every bobbin change. And Huskies don't require oiling (as I recently found out).
So I guess I would recommend finding a realiable service man. Bring the machine in now and ask him everything he had to do, and how often he recommends doing it in the future. If he thinks you waited too long, bring it back in two years and ask again everything he had to do - then take it from there.