I was originally told I could empty the water every 2-3 days, but I like to clean my hose on the same day I empty the water. It's easier to keep track of. It seems like there is a lot of varying information out there on how to keep the apparatus clean. I prefer the distilled vinegar because otherwise I'd have to wash the hose daily with soap and water. When I travel and can't get the vinegar, I clean every day. I'm willing to put up with the cleaning if I can get a good night's sleep. I wish there was some good scientific information on the best way to clean and on frequency. Anybody have such information?