Using the showers was by far THE best tip I ever got on the Dis! We had a 3-night cruise on the Dream last month and every morning I would get up early, walk around the empty ship and then take a small bag of bathroom stuff and the day's outfit and use the showers.
The showers were AWESOME. Very large, plenty of hot water, with the rainshower type of shower head.
I highly recommend this. Since there were 4 of us in the room, it helped immensely for me to shower elsewhere. It was ME time and I loved it!