How long can I go without a shower? Not long. After 24-hours my hair is greasy and stringy, which makes me feel grubby and gross. I have, for various reasons, gone as long as 4 days without one. The first 2 were not too bad, but by the 4th I was a raving loony. Every inch of my skin itched. Especially my scalp. I had to wear a do-rag to hide my mess of a head.
I was ugly and I wanted to hide under a rock. I fantasized about hot steamy showers, big fluffy white towels, and shampoo suds. The bottoms of my feet itched so bad that I had to jump up and down, stomping hard on the floor. I looked like a bad tantrum happening.
So to answer your question – 2 days.