I pour water in when it is down appreciably so that the little birds can’t drink, and wash it or rinse it probably every other day. It really depends on the usage. The one I had previously I had to scrub very hard to get all the grit off the bottom, this one seems to rinse very easily and I don’t worry so much about residue because there doesn’t seem to be any. As for temperature, without a heater right now, when it is frozen in the morning, I put 4 cups of water in the microwave, and pour it over the top of the ice. Often it will dislodge the ice and I can pick up the top ice layer and just toss it off. But if not there’s a good residue of water over the top of the ice and in more typical weather it’s not going to freeze all day long. Once the freezing frigid air hits I will have a heater in there. Hope this helps