Does your bar have a stage? How often do bands play at your bar? Do you notice more or fewer customers on nights that you have a band playing?
Booking quality bands is important for growing your customer base. Don't stress too much about the genre of the music. If you only book bands that play rock you'll miss out on country music fans as potential paying customers.
If the band mainly plays covers they need to be top notch. When covering a popular song it needs to be pretty damn close to the original song. This means specific drum fills, bass walks, and guitar solos have to be on the money. Getting a crowd pumped means giving them a common ground of enjoyment so they pump each other up.
Booking bands that aren't really that good will be more memorable than the good bands. Unfortunate, but that's the way it is.
Different Types of Bars Does Impact the Decision
If you work at a members only club that the majority of your customers are over 65, well hard rock is obviously not the way to go. Book bands that are easy for folks to dance to.
But still branch out. Even if your customers continually attend your bar on nights that the same band that always plays is there, I assure you they will appreciate the variety.
And don't forget how important it is to support your local businesses including musicians and bands.
How to Find Good Local Bands
There are bands in your town you've never heard of. You need to go out this weekend to bars you've never or rarely go to. Talk to people. Ask strangers about their favorite local bands. You'll learn what you need to. Not everyone has an online presence (believe it or not). Word of mouth is still powerful.