questions about Irradiance caching and AO

does it make it better with 99? yes it does. but we did only tests with white shaders and 100% AO. so there we notice a lot of change.

but after we have props,figures,textures,different shaders do we notice I C 50 or even  20? i sometimes use IC 10 and i dont think you would notice that AO looks bad.

so do we always notice IC99 in renders ? because rendertime is very longer.