lol. i change mine once a week along with all the newspaper...i also clean out the bowl with soap. none of mine poop in there bowl. but if something else gets in there i clean it out sooner.
my snake doesnt like to soak in the water but i still clean the water everyday. the way i see it is that i dont like to drink water that has been out for a few days because of all the microorganisms that are in the air and land on the water.
(I saw this movie in science that was very disturbing about all the micro-organisms around us)