How long should a sewing machine last?

It depends almost entirely on the frame and on whether anyone cleans it.

A metal-framed mechanical machine, cleaned regularly and serviced occasionally, lasts decades. There are working machines from the 1950s in daily use. The mechanism is simple, the parts are replaceable, and nothing in it goes out of date.

A plastic-framed machine gives good service for years rather than decades. The frame flexes under load, which gradually shifts the relationship between needle bar and hook. That shows up as skipped stitches and timing that needs resetting, and eventually as a machine not worth the cost of the repair.

A computerised machine adds a third factor: electronics. In practice they last well, but the failure mode is different — a board fault is not something a general repairer fixes, and after some years the board may not be available.

What actually determines lifespan in practice:

• Cleaning. Lint in the bobbin race is what kills most machines, and it takes two minutes to prevent.
• Whether a dealer stocks parts for your brand where you live.
• Whether you use the right needle, which prevents the strikes that damage timing.

The buying implication. If you want a machine for decades, weight and a stated metal frame matter more than any feature on the box — and a dealer network matters more than both.