My two main reasons for change are: A new project someone ordered 2) thumping sound when sewing. When I make s-g just for fun/myself I'm not that particular, for PP projects for myself I may take an older needle to replace a thumping one, might get a block or two, and also if I have a lot of basting or ruffles to do. I often save needles when I have to start a new project someone ordered.Low income - small pension, that's why.