When I bought my pfaff almost twenty years ago I asked the dealer if I should bring it in once a year for service.
"Ah madam": he replied, "when we give it a service we blow it to clean and put some oil in it....you can save money by doing that yourself."
So I did, and still do, my machine has never been back to the dealer.
And the dealer was one of the two bestknown for good service in the area.
But with the machines of today?? Don't know if I should do the same, they're not all the workhorses the old ones used to be , I hear people say