I do small pieces with many colors of thread used for the stitching. It’s helpful to have lots of bobbins ready to go. I have a doughnut holder of bobbins too. I notice that only a couple of my bobbins are empty at the moment. Generally I have 6-10 empty. These are just for the bernina.
Looks like a color system. Keeping same kind of bobbins very important. Like you I have at least three systems. Juki, Jamone , and featherweight. Always bobbins ready to go.
Beautiful!