According to this article on cacti
During the low-light winter months, cacti and succulents should be watered only enough to prevent shrinking and withering. When watering, do it thoroughly. Water should flow through the drain holes, and the excess should be discarded after a few minutes. A series of repeated shallow sprinklings often results in distorted growth. As the amount of light increases in the spring, so does the plant's need for water. The soil, however, should always be allowed to dry out completely between waterings.
How often you need to water is a result of how well drained your soil is, the size of the pot, the size of the plant, how much sun it gets, how dry the air is in your home. All that being said, let the soil get dry to the touch but then water the pot until it runs out the drain hole.
I hope this helps.