First off to keep things in perspective . . . I work for the company that is the exclusive importer of SCHMETZ Household Needles into the North American Marketplace. Most of our sales are to distributors but we do also have a small retail web site. I get asked this question a lot by consumers. The SCHMETZ company line is to change your needle every 8 hours on average or whenever starting a new project. That being said, nothing beats the request I received a few years ago from a customer who was looking to purchase the exact SCHMETZ needle that was in her sewing machine. She was extremely proud that she had been using the same needle for 15 years and it finally broke. I didn't have the heart to ask her what her stitches looked like.