Christmas cactus are drought tolerant plants that can survive in a wide range of temperatures and conditions, but they do require regular watering to thrive. Typically, you should water your Christmas cactus once every week or two, depending on the humidity and temperature of your home. During the summer, you may need to water more frequently to prevent the soil from drying out completely. However, it's important to avoid overwatering, as this can cause root rot and other problems.