Agave americana is probably the most common agave world wide. In many parts of the world it is almost a weed, with the prolific offsets. Even in the UK as one of the hardy agaves it is the one you will see in peoples gardens, and the odd news paper when they flower. The different varieties of this plant can pretty much represent the changes many succulent collections go through.
Once you have a few agaves many people start to look at variegated plants, only slightly less common is the marginata form. Again my first variegated agave, and it was given pride of place in the garden for a while.
By now, you are probably getting fussy and each plant is worthy of a place. This means that it is more difficult to decide what to do when space runs out. Medio-picta alba is a lovely, too good to just bin, so it gets shifted into a less prominent place and this is the dance that happens with each new plant.
You may feel that agave americana is too common, so lets change to the plants that have come out recently. Starting with agave blue glow, soon you're moving on to the variegates snow glow and sun glow. What's that a new one just about to be released! The plants may have changed but the story is always the same. I wonder what we would think if agave americana wasn't on every street, if it was a hybrid just coming onto the market?