The shirt dilemma

Okay, so I have a busy day tomorrow at the NCTOH Conference we're hosting in Phoenix. I'm in charge of our college tobacco prevention program called IGNITE, and am meeting up with a whole group of IGNITE students who we're sponsoring to attend the conference. Therefore, I have to wear the black IGNITE shirt on the right in the morning so that we can easily identify each other. The blue shirt on the left is my volunteer shirt that I then have to wear in the afternoon while I'm filling my volunteer responsibilities monitoring some of the breakout sessions. Well taking an extra T-shirt and changing at some point during the day is not really a big issue, the dilemma comes while trying to decide what to wear when I present my poster session at 11 am. You see I'm technically a presenter, so I ought to dress professionally, but it is just a poster presentation, so I'll just be standing by my poster answering questions, and it's not like I'll be at a podium in front of everyone.
So the logical part of me is tempted to think that two t-shirts a day is enough and I don't really need to bother with changing a third time, but then the professional part of me thinks I ought to take another, more professional looking shirt to wear during my poster session, and last but not least, the realistic part of me has to think, to adapt an analogy from one of my favorite conference talks (see Slow to Anger, Oct 2007), that half the people who are there won't even come by my poster session, and half of those who do won't even notice what I'm wearing, and of the half that do notice what I'm wearing, half of them won't even care, and the half that do are of little consequence anyways. But even so, when all is said and done, I'm still not quite sure what I'm going to do tomorrow about the shirt dilemma.