I have the Brother equivalent of your machine. I use whatever the heck I want to buy depending on what color I need. I try to always use colored bobbin thread in 60 weight in my bobbins, but I have trouble finding a lot of color choices in the 60 weight thread. For the top thread I like rayon thread best, then polyester, and I buy mine from a supplier in Great Britain who buys thread made in Pakistan. The small size - 250 yds- cost me about $1 but I only can get about 25 colors. The other colors I buy the best buy I can f ind including prices up to$9 a spool. Cuss words! I hate paying top dollar for a color because I need just that one for a particular shading, etc. I don't automatically go with the colors suggested with a design because, don't you know, my 4 shades of brown won't include the shade they want. Also, I may love the design, but the main color may be red when I need the main color to be blue, so I have to reassign colors. I bought a color chart for R-A thread to help me locate the right colors in other brands of thread - my machine only includes the colors for 4 major brands. The chart really helps. I has a couple hundred of colors shown. I think I have less than a hundred in my thread stash now.