I have magnetic postcards stuck to the base of my antique machines at the quarter inch mark, and check them periodically for movement. I have 2 different antique Singers based in different rooms so I can sew while watching TV or sew while the longarm is quilting. Then I have my Aria in the basement and my Juki industrial straight stitch machine, which I use mostly for putting on borders or any long seams that are nice to sew fast. I check frequently to make sure my seams are accurate. If I am working on precision blocks I will use just one machine, but most of my quilts are charity quilts not requiring such precision.