I just spot clean when I need to. I'm looking in on them multiple times daily anyway so I notice things really fast. I change out their water every 2 or 3 days unless something dictates I do it more frequently. Like substrate in the water dish or something like that. I do a deep cleaning of water dishes once a week or so. I deep clean tubs every 10 days or so. Usually when I change substrate or if someone makes a big mess. I don't have tons of snakes like some of you guys do and time isn't an issue so I haven't been forced to regiment myself so much.