Before revision: We consider an infinite-horizon optimal consumption problem for an individual who forms a consumption habit based on an exponentially-weighted average of her past rate of consumption. The novelty of our approach is in introducing habit formation through a constraint, rather than through the objective function, as is customary in the existing habit-formation literature. Specifically, we require that the individual  consume at a rate that is greater than a certain proportion \alpha\le1 of her consumption habit .
After revision: We propose a new optimal consumption model in which the degree of addictiveness of habit formation is directly controlled through a consumption constraint. In particular, we assume that the individual consume at a rate that is greater than a certain proportion \alpha\le1 of her consumption habit .