they pretty much make you do it in boot camp. You don't have to, but if you do you get juice and cookies and you get to sleep at a desk for a few minutes, so everyone does lol
other than that, mofo's have been bleeding me dry running all the bloodwork for my latest series of ailments...
You have 8 pints, a friend of mine's dad lost 6 when he severed an artery on his arm before he got to the hospital. I don't know what the number is where most people give out, but I'm pretty sure not many people lose 6 and live like him...