Like any other plant, how often you water a succulent or cactus will depend on the season, the size of the pot its in, the temperature, the humidity, and the light it gets. Succulents and cacti like to be watered like your typical houseplant: deeply and until runoff is achieved.
The main difference here is that succulents and cacti like to go much longer in between waterings. A good way to think about this is to consider how they live in their natural environments. Succulents and cacti thrive in rocky, sandy, and dry areas with very little rainfall, so they're used to getting one big drink every once in a while.
While I may water a pothos once a week, a succulent in a comparable size pot may only be watered every 2-3 weeks. However, I also have many tiny succulents in little pots on my windowsills. If the temperature is high and the sun is intense, I can sometimes even water them more than once a week.
In winter, you'll want to water even less often. Many cacti and succulents go dormant during the winter due to colder temperatures and shorter days. Even though they're inside, I water mine less.
In general good watering for succulents and cacti come down to one major rule: never, ever water until the soil is completely dry. They have very shallow roots and are extremely susceptible to root rot, so it is very important to let them have a dry period between waterings.