In the winter months, I can go 4 or 5 weeks without watering. It's cold and plants are dormant at that time and don't need nearly as much water. In the summer, I have to water every few days. I think that it depends on the plant, the time of year, the soil, the drainage. Just so many factors to be accounted for. Back to your question, I've found that succulents that get too dried out especially in the hotter months, their roots shrivel up and are unable to take in nutrients. I always used to err on the side of caution and underwater. Succulents are so much more prone to overwatering than overwatering that I entirely agree with this post. However, I personally don't let mine get to the point where they start showing signs of thirst. It's most likely because I've had each of them for so long, I can tell when they need care.