What kind of textures I should bake for a given Shader?

Hi all,

Cycles material system is vast. How do I know what kind of textures I should bake for a given Shader?
For example, in a shader there is only a diffuse image specified. Nothing else is specified. In that case, we need not bake Normal map as it is not required.

I need to bake textures for a given Cycles scene and export the scene into a standard format like fbx. This fully baked scene will later be imported into other application like a game.

So, I should determine what kind of textures I should bake.

Please help me.