It depends of the game. A game using a third person view will need a certain amount of bones while a top-down shooter will probably need less simply because the camera is not located at the same distance. A fight game (such as Street Fighter for example) needs a lot more bones because animations are in the core of the…
also make sure you check with your coders about the limitations of the engine your using. UDK for example has a 75 bone limit before it splits the mesh up treating it as a separate mesh, increasing your draw calls etc.