The Silver Dollar Vine is a rare plant, all the way from Madagascar. They do best in a well-lit spot with some direct morning sun. Wait until the soil is totally dry before watering again. If you are unsure if it's time you can wait to water until the plant itself starts to wrinkle a little, as that is a good indication the plant is losing water. Like most plants with succulent leaves, they are adapted to and prefer dry soils.