I love the ideas of forth, have been toying around with them in factor of factorcode.org recently. How many resources should that smart compiler be able to use

I love the ideas of forth, have been toying around with them in factor of factorcode.org recently. How many resources should that smart compiler be able to use ? The problems of optimization become important when you are about to run out of resouces... If you are out of resources, why would you leave some for the compiler ?