Do You Know This?

On deodorant bottles, why is it specified to spray from a distance of 15 cms or 6 inches?
The deodorant cans are pressurised cans which eject
the spray of deodorant from a single point source.
Consequently, the spray diverges and spreads widely
as it moves away from the source of ejection.
Thus if the can is held too close to the skin then very less area of skin gets sprayed with too much of deodorant, making the process wasteful;
while if the can is held at a distance of more than 15 cm
the concentration of deodorant over the skin becomes too less
and this renders it ineffective.
A distance of 15 cm ensures that just the right amount of deodorant is sprayed over the unit surface area of skin thus making it most effective
--Aj