Agave is listed in the free booklet from the City of Austin as a good choice for growing here in Austin, thanks to its adaptability and its very light water requirements. It's also a great choice for folks who have to deal with deer munching on their garden plants. The spiky leaves are enough to keep deer away.
Those spines are also a big reason gardeners should think long and hard about where to place agave, because they're not fun to transplant. I have learned the hard way, believe me. But if you do need to move one, make sure you protect yourself with long sleeves, heavy pants and thick gloves. I also recommend eye protection, on the off-chance you lean in a little too far when picking it up. I'm a klutz -- I'm not afraid to admit it.
There are dozens of different varieties of agave, so if get your hands on one from a neighbor or friend, find out as much as you can about its habit before you take it home. If you decide to by one from a local nursery, ask the staff as many questions as you can -- don't rely solely on the plant labels. It will help you, I promise when you plant it.
Other than those few precautions, there's little else you need to do with agave. That's the beauty of this plant. It's a tough little thing and hardly needs any water. It even establishes itself in rocky, clay-heavy soils, as my mother in Atlanta reported to me not long ago.
So the next time you see a garden full of agave, strike up a conversation with the owner. They might just let you take one home.