Succulents are massive right now. They're in commercials, magazines and in restaurants. They're beautiful and fascinating, but easy to grow.
Succulents thrive on neglect. The best way to kill them is with kindness. Over-watering them will be their doom. They can easily go three weeks without water.
All cactus are succulents but not all succulents are cactus. A cactus is generally distinguished by its protective spines. These deter desert animals from eating them. Cactus and succulents usually don't have extensive root systems but instead store water above ground in their thick leaves and stems.
There are hundreds and hundreds--even thousands--of succulents suitable for growing in your house and outdoors. Hardy types include ice plants, sedums, hens 'n chicks, yuccas and hardy cactus. Popular indoor types include jade plant, echeveria, aloe, agave and tropical cactus.
Succulents rarely need re-potting. When they do outgrow a pot--or if you're moving them from a plastic nursery pot to a clay one--water them well first. This will help hold the root ball intact.
Select a pot that's just slightly larger. Potting mixes formulated just for succulents are available but you can make your own by adding fine gravel to a standard potting mix. After planting, top dress the soil with a layer of fine gravel. This mimics the natural conditions where most cactus and succulents grow.
Most cactus and succulents have pretty flowers (cactus flowers are often stunningly beautiful) but most are produced in summer. If you take your collection outside in May, expose the plants to sunlight very gradually over a period of weeks. They can easily burn. This will disfigure them for a long time--even years--so be very careful.
Because of high summer heat, these plants will need slightly more water. Soak them thoroughly every few weeks and forget them. If you're confused about when to water, get a moisture meter.
If you consider yourself a negligent gardener, these are the plants for you. Bright light and low water will yield big results.