I'm a bit OCD about running out of floss, too, so if I have any qualms about the thread quantity in a kit, I sub in something from my floss stash that's as close as possible. I do save the floss that I didn't use and either save it for some other project or donate it to a specific organization where there are disabled clients who love to stitch, knit, crochet, etc., but don't have the money to buy supplies or access, either by transportation or internet, to get it themselves.