It depends on your climate. You might not need to supplementally water them if you live in a region with summer rains. They're known for being drought-resistant perennials and will succumb to wet conditions. In Santa Barbara, my Echeverias were drip irrigated every 10 days in summer and early fall along with the rest of my garden. Newly planted Hens and Chicks will need to be watered on a regular basis to get them established. Hens and Chicks in pots (especially low bowls) will need to be watered every 7-14 days.