I start at the time the management has hired me for, whether there is anybody there with a slip or not.The one venue I do we start at 10PM and go until 2AM.Quite often, there is very few people until 11,so I will have some fun trying out some songs that I'd like to work on, and this gives the few that are there a chance to see that I'm not there to be "perfect" and it will even encourage some people to try it out, then they get more courage for when there are more people there, and what do you know, another regular singer has evolved.
Have fun or go home!!