I don't touch a drop when I am driving and I don't accept alcohol from a customer if they offer me a drink.
The only time I will have a drink or two is if I am DJing at my local and I have the following day off. I can leave the minimal amount of equipment there where it is locked away safe and secure and get it the following day.
Sometimes at my one of my hotel residencies I may have one after the function with the staff and that's out the back away from the guests. I'll walk home and pack up the following day as it's only 5 minutes away, this is if they don't have another function on. If they do then I know in advance so I wouldn't have a drink if that's the case.