I wouldn't call myself obsessed with cleanliness. I will quite happily wear the same clothes two days in a row if they don't stink, and if I've just swum in the evening and know I have to swim again in the morning, I'll often forgo a shower as well - because what would be the point? However, I just can't deal with going for longer than every other day. Even though I only have three inches of hair, it starts to feel incredibly disgusting if it doesn't get cleaned every day or two.
I'm not talking about camping trips or other extenuating circumstances, by the way. On Semester at Sea, I know there will be times in Africa and India when I'll have to skip a shower for four or five days at a time, and it won't be a problem at all - because it's all part of the experience. But at the moment, I am living in a perfectly normal living situation - in a perfectly normal house equipped with a perfectly normal bathroom - and I want my effing shower!