Sewing machines need an occasional tune-up and service like any other machine. How often you need to do that depends on how much you use it. Some manufacturers recommend servicing after every 100 hours of use, but if you’re doing regular cleaning and oiling, you can probably go longer between tune-ups. If you’re using the machine regularly, a yearly or a twice-yearly visit to a reputable repair shop should suffice. Talk to your local craft or sewing store if you’re not sure where to find sewing machine repair services.