I think it also depends on what types of fabric you are sewing on. Some fabrics, like minky or acrylic fur, will really jam up your machine in a hurry. Also some brands of thread produce more lint than others. My wonderful repairman has kept my 40+year-old Viking workhorse going for over 20 years, and never once has he tried to sell me a new machine. To add an unrelated piece of useful information, his #1 recommendation to getting a true and quality stitch is frequently replacing your needle, even if it seems ok.