It depends on many things, but one is sure. More than 5 sprays always irritates everyone around you.
I spray 4 times - all of them on my neck. And I think it's absolutely enough. But it depends on the scent, weather, type of the skin you have..... If it is a hot august noon and you want to wear something "heavy" like M7 you should spray 2 or 3 times (even too much). The purpose of the fragrances is smelling good and being oversprayed isn't good at all