When is enough enough? Enough of anything. Think about how easily dissatisfied the human becomes once it gets a taste of something pleasurable. Soon you are even dissatisfied merely thinking about when you will no longer have that thing or when and where you can get more of it. This applies to most everything in your life, not just food and alcohol and the like. The ego loves its addictions, most especially the addiction to thinking and emotions. These are its greatest tools for keeping you thinking you are separate from others.
Be present. Think not about the future. Dwell not on the past. Pay attention to what you are doing. Be fully present with others and the activities you are involved in, and you will find your addictions lessening as you diminish ego’s addictive personality.