When I buy emb thread I always try to get two or three in the same color scheme because just about all designs end up using shades a little different for shading effects. The size of the spool depends on the cost, the amount I'll use or its popularity and the size of my wallet on that day. I try to keep some in all color schemes so that I dont' have to worry about having the right colors for a design. My software allows me to use the thread manger to enter in all of my thread and then I tell it to pick the closest colors from what I own to match what is called for in the orginal design. I really love doing this when I use varigated thread (which I love) because it will show me how it'll look stitched out. This is important depending on the design. At a retreat this weekend there was a pine tree in the design and the person used varigated thread on the tree. It would of been cool if the stitches went side to side but it went from top of tree to bottom and that didn't look to good. Good luck with your new adventure. I love doing it and I'm doing another retreat the end of the month for a quilt called Oh la la, its so pretty.