Not CONSISTENTLY marketing to your prospective and existing customers is bad. Why? It has to do with what we call "The Buying Spectrum". Think of a grove of orange trees. Once the oranges are in season they begin to ripen. Now it's time to pick the ripe ones. Yet do you think that all of the oranges on all of the trees ripen all at the same time? Of course not.
So you go through picking only the ripe ones and leaving the green unripened oranges still on the tree. Now that you've gotten all of the ripened oranges you leave the orange grove never to return right? Wrong! Yet this is exactly what many businesses do.