For us, usually at the rehearsal immediately prior to a gig, we’ll focus on making it like the gig as much as possible. The band leader may not rehearse each word she’s going to say for banter, but she‘s kind of developed an “outline”, if you will, of the kinds of things she’ll say.
But, she’s also good at reading the crowd and doing things very impromptu to perpetuate the energy.
You "get it."