You do not have to use bone layers to show/hide some bones. As with objects, vertices or control points, you can use H:
H will hide the selected bone(s).
Shift-H will hide all bones but the selected one(s).
Alt-H will show all hidden bones.
You can also use the Hide checkbox of the.
Note that hidden bones are specific to a mode, i.e. you can hide some bones in Edit Mode, they will still be visible in Pose Mode, and vice versa. Hidden bones in Pose Mode are also invisible in Object Mode. And in Edit Mode, the bone to hide must be fully selected, not just its root or tip.