Programming rules are important - they make you think before you break them. Just don't turn rules into dogma - otherwise your devs will be more concerned with following the rules than solving the actual business problems. And you don't want that.
Rules should help you along, perhaps set a framework for your thinking. But they never should limit you in achieving your goal. When establishing a rule you should also specify what you want to achieve by it, how you'll measure its effects and under which conditions it should be removed.
Rigid rule enforcement has a strong danger of shifting the priorities of the developers to the detriment of your business.