I have neutrals and often used colors of my piecing thread in my machine accessories boxes, right with the feet, etc, next to each machine. Then I have bobbins on the red plastic things that hold your spool and bobbin together, for less frequently used threads. I have a bobbin donut with the bobbins left from a crappy ol' machine I had for many years. My kids use that thread for hand sewing practice and unimportant stuff. I have a bobbin donut I bought from Connecting Threads filled with 36 different colors of Masterpiece. I've been using that for hand appliqué, with great results. I keep my thread in plastic boxes in a drawer, away from dust and light, so some bobbins go in there, next to the matching spools. Finally, I have some bobbins of my machine quilting thread in a tray. My main machines use bobbins which are easily distinguished from each other and the only bobbins which aren't with the matching spools of thread are the piecing threads and some quilting threads labeled by wt (40, 28, 12). HTH :)