There were 3 bobbins included with my machine, the sew/vac place that I got my new machine at gave me another 5 and I bought a few more.
I have a tendancy to keep my bobbins filled after finsihing a project and a few with basic colors. I spent some time filling bobbins with some of my most used colors and colors currently in use.
If you are new to sewing I recomend keeping the following list of colors on your bobbins.
and denim colors (including the yellowish color that many denim jeans are sewn with)
and any other color that you will use alot, in my case that includes orange, camo colors, blue, pink, purple.
I don’t have all the colors wound yet but I will wait with the rest of the colors until I have projects coming up in thoose colors. Having filled bobbins is also great to grab (as well as a needle) when you may need a sewing kit for a few emergency repairs, it won’t take up much space and you can easily match the thread to what you are wearing, or even what an entire bridal party is wearing.