I have a D1 and a DIamond. I use the green ones, and there are also multi-colored ones available. But I do use pre-wound (both plastic and cardboard sided) almost all the time. Only use "colored" bobbins when I need to match bobbin thread. I bought a gross of white and black pre-wound and haven't had to buy more! I think the problem is when you are using bobbins that don't fit, but I haven't had an issue unless I try to use the clear ones for the little Janome, then they don't work!!