What ever I put in my top, I put in my bobbin. I don't want to have to worry about it. My machine tells me when I'm running low and is easy to change. I try to do extra bobbins when needed but my machine will wind them while its still threaded. I love Aurifil thread, I get more accurate seams using it. I do the same thing when doing embroidery. Its always the same type, depending on how much stabilizer I might be using I may have different colors as long as I'm sure it won't show thru.