Whether you are a musician or someone who makes a living from selling music on the business side of things - recorded or live - the last thing you ever want a fan to think is, "yes, I'm completely satisfied, thanks." You don't to ever leave them displeased, of course - every show, every piece of music you release should be designed to maintain fans and earn new ones - but leaving them slightly hungry is a different matter all together. In other words, always leave your fans wanting more, whether it is one more encore or one more track. If they don't want more, why would they ever go looking for (and buying) more? And if they don't - where would that leave you?
This rule is fairly intuitive. After all, we've all been to shows where the audience keeps on cheering and stomping their feet even after the house lights come up, hoping against hope that the band will come back and do just one more. However,where things get tricky is when you are still essentially operating on the local level. When all - or the vast majority of - your shows are local, how often should you be playing?
There are a lot of benefits to playing live, whether you're touring or playing exclusively local shows. You get to hone your set. You get comfortable in front of an audience. You build your fan base. You make your name known to the local press. These are all great things. The problem comes in when you begin to saturate the area. If you play too many shows, suddenly you don't seem so special, no matter how devoted your fans are. If they just saw you last week and can see you again next week, this week's show might take a back seat to a night at the movies, a co-worker's birthday party, a night with the DVR or yes, another band's show. Does it mean they don't like your music? No, but it means that it no longer seems all that special, and they take it for granted that you're always going to be around, like Law and Order re-runs.
Instead of playing in the same playground every day, start treating your shows as events. Play often enough that no one is forgetting about you, but not so often that going to see you becomes routine. Is there a simple formula to tell you how often you should play locally? No, that would be too...well...simple. But if you are consistently out there every three or four weeks, you may be overdoing it. Depending on the size of the music community in your area, playing every six weeks could be too much. Read your crowd to develop your own formula. Are you numbers going down instead of up, without a good explanation (such as your last two shows happened to fall on nights when a major touring act was in town)? Do you recognize almost everyone in your audience? Is it harder to get local press coverage of your show, since, hey, they can only cover you so much? These things are all red flags that you may be flooding your own market.
That's the story for local folks, but if you're on the road, the same rules apply. Many promoters/venues include a clause in their contracts forbidding you from playing within a certain radius of the club a certain number of weeks before or after the show they have booked with you. Why? Because they want THEIR show to be the event, and the more options people have for seeing you, the less pressed they will feel to be at THAT show. Even if you don't have such a contract, the rule is a sound one you should consider self-enforcing.
The bottom line? Don't ever let your fans decide that they have had their fill. Give them a reason to keep coming back by treating your music and your shows as special events instead of constantly available fillers. It will keep your listeners engaged for longer.