"dead nights" like Sunday and Monday? I've played several shows on these days, a few gigs were around 5000 in attendance, most had 500-1000. I suppose it's who your playing with and where. Then again, I have played for 10-20 people on any given night as well.
...unless you just want a dress rehearsal you can get a lot more done at the practice pad. Now, I've played to an almost empty house for decent wages and I've played to a packed festival for zilch and there was some satisfaction out of both of those situations...but to put forth the effort to move gear, set up and play for the bartender (unless she's really hot and into you)...well that situation should be avoided if at all possible.