I keep plenty of white, gray and ecru on hand but also have a serious collection of colored thread in case I need to use them. When machine quilting. I uusually use a matching thread on the bottom and whatever will hide best on the top which I am surprised sometimes by what will work. I recently used purple on the top and it worked well. Several quilting friends were horrified by my use of purple but I quilt for myself and not to make others happy. :):):)