I have an 830 that I've had since they came out in something like 1975, I've sewed on that machine for days straight for years on end.. Never have had a problem.. I also have a 1230 that I've used about as much since I got it.. I generally have more than one project going and use either one machine or the other.. Or I'll use one machine for sewing the other for topstitching when it's in a different color... I have never had one minute of a problem with either machine.