Hey Gregg,
If I am going to use the Sous Vide the next day I leave the water in, other wise I dispose of the water and dry out my gear. I have only had my unit for a couple of months, so far it has not needed to be cleaned. Here is what Anova says about cleaning:
Simply dilute equal parts water and white vinegar into a small pot. Put your Anova Precision Cooker in the water-vinegar combo. Set the temperature to 140 °F / 60 °C, and allow the device to heat the liquid. When the device has reached that temperature, the cleaning is complete.
Best Greg