There so many great species to choose, especially as more gardeners look for low-water plants in our continued drought. Before choosing yours, consider their mature size and stick-ability! You don’t want a huge agave at maturity to overwhelm your space or stab people walking on a pathway. Some, like the squid agave (A. bracteosa) have softer leaves and remain smaller.
There are many colors, forms and sizes, so choose the ones that complement your garden.
Like the very large century plant (Agave americana) most agaves take quite a while to bloom. Mostly there are monocarpic, meaning that they die after blooming. There are some exceptions like the squid agave.
But even before flowering, most likely you’ll have baby plants (offsets) around the mother plant. These plantlets are basically little clones, and can be dug up and planted in other areas, or placed in containers, so that you’ll have a replacement for that spot when the original plant dies.
All agaves need well-drained soil, so if you have heavy clay and can’t change it, you should choose other low-water plants. If you can amend the planting area, replace the clay with very sandy soil, mixed with coarser decomposed granite or expanded shale, and consider building bermed areas, so that drainage is increased even more with the elevation.
Or, plant them in well-drained containers as accents.
Also, be sure to know their origin. Some agaves are native to Central Texas and can take our occasional cold winters just fine. Agaves that are native to the Chihuahuan desert would also be good for our area, since their native region has cold winters. But agaves native to the Sonoran desert of southern Arizona are not accustomed to the cold, and should be protected in winter.
So, do take a look at the plant tag at its cold hardiness, and whether it’s one for the ground or a pot to protect in winter.