Just sustanon, and no orals? I see no issue with that (in moderation of a couple beers on the weekends). With orals its a different issue due to increased toxicity of the liver, etc..
I know a lot of guys will flame people on here for having some drinks socially every now and then while on cycle, but its really not a big deal. I have 2 or 3 beers on a Saturday night maybe twice a month myself whether on cycle or not. The only time I wouldn't is if I was in prep for a contest. I still progress very very well. Too each their own, but in my opinion life is too short to become a zealot. Unless your job is a professional bodybuilder I see no reason to let your lifestyle get in the way of life.