Native to South Africa, these clump forming succulent plants have similarities with the Aloe plant and they're related with the same sub-family. There are also sub-species grown.
In their natural habitat (sub-tropical) they receive plenty of sun and periods without rainfall. Their succulent nature enables them to store water within the thick leaves when there's no frequent rainfall.
Display this plant anywhere it can receive plenty of sun or bright light. South facing windows will provide the most sun, however, east or west provide direct sun part of the day that I find more suitable.
During the growing season from April - September water the plant thoroughly and then water when the soil becomes dry to the touch (not bone dry though). Winter is a tricky time for these plants although they are a tough species. Many growers will overwater then alongside cold temperatures or drafts the plant can become very sick, or even die. The leaves are storage organs so during the winter water much less and allow the top soil to dry out