my kids are all on cypress mulch in boaphiles and they like to "go" in the same little spots pretty much all the time, so i only clean where they soil. After 2-3 months the substrate is still 95% clean. Once i get my rack i'll probably go over to paper and start with the weekly cleanings. I can see why you have to change the paper as soon as its wet or soiled.
As for the chlorhexidine, when i let my water dishes soak in it i really rinse them very well with hot water afterwards because im afraid of too much chemical residue in the water dish. I know its safe, but do you guys do this also? Maybe im worrying too much, but the water dishes are the one thing i really want to make sure are rinsed well.