Just don't rely on the caffeine too much. With my musical opening this week, last week was quite busy and I wasn't getting much sleep, so I was having a cup here and a cup there (only like 3 cups total that week). Normally, the medication for my ADD that I take gives me a caffeine like boost as well, so coffee is normally unnecessary for me. Well, I must have pushed myself too hard because about a half hour after I had a cup (while on my way home), I started to feel really hot. Eventually I started feeling extremely nauseous. In the car, I had to put the AC on full blast and was taking off as many clothes as could legally take off including my bra. When I got home, I immediately got in a cold bath and sat there as long as possible. Several times that night I ended up vomiting a lovely coffee colored liquid (yuck!) and had to miss my rehearsal. It felt like I had the stomach flu even though I didn't have a temperature. Eventually I was able to get to sleep and I got a nice 11 hours (and I'm still recovering). My point is, if you push yourself too hard, and rely on the caffeine, you could really end up having to go through a miserable experience like I did.