
I use 3 types of stitch holders. The small orange and green locking clips are suitable for holding a few stitches. I use them to hold a dropped stitch until I can repair it and to hold edge stitches that will be later worked into an I-cord or button band.
For years the metal loops (approximate clothes hanger wire gauge) were my workhorses and I still use them to hold small spans of stitches, for example in pocket construction.
My new workshorses are the versatile Knit Picks cables with screw-on caps (purple in photo). These can hold a large number of stitches without dropping any and can be marked with the needle gauge (see needle size labels below). They have great portability, due to the flexible cables and come in various lengths. When you are again ready to knit the reserved stitches, you just attach the needle tips.