I agree with everyone else. You can never have too many bobbins!! If I do have to remove some thread I take what has the least, except for my four basic colors, white, black, beige and navy. I find I use those colors most often, when mending. I do other sewing besides the quilting, so I do have alot of colors. I have several of the plastic flexible bobbin savers. I use different bobbins in the Bernina and the old Singer so that helps keep them separate. I always try to have a couple of extra empty bobbins on hand too. When I use the same thread on top and bobbin in my longarm, I tuck the left over filled bobbins in the thread cone and tuck in a bit of scrap batting. If the batting is there, I know I have at least a partially filled bobbin in there. Hope this helps.