Why are stoichiometric calculations so important in industrial production of chemical substances?

Stoichiometric calculations are so important in the industrial production of chemical substances because through these calculations you are able to derive many things involved in the essence of that branches intentions. 

First the correct amounts of which substances must be added , the specific limiting reagent to ensure the process has enough of each reactant to proceed, and the theoretical yield that will roughly estimate the amount of product received from the reaction.

This branch of chemistry mainly deals in the mass production of various chemical substances so these factors are pivotal to the field.