Well, the general rule in our band - even if we're learning new material - is do your homework at home and come prepared. You have brain farts and nothing is ever perfect, but if one person isn't doing his or her job, it is a bit disrespectful. The other singer showed you what it could be, but you also shouldn't need a million rehearsals to get it together, either. If everyone's on the same page, it should come together quickly. We just switched singers and it hasn't taken much time at all to get up to speed and we're coming up on our second live gig with her.