Sometimes, I think you have to be careful not to be conned. A friend who does little sewing was told she needed an expensive repair on her machine and it was better to buy a new machine. She bought the new machine. I took her old machine to my repair man and he serviced it for $40 - it just needed a lint clean out.It is a Pfaff and runs perfectly now.
Then she was told she needed a repair on her new machine - I threaded it correctly for her and it works perfectly. So that means I tend to do the repairs and maintenance that I am capable of and will only take them in if I can't fix them.