Among the oldest textile materials, wool has been around for many millenia and for good reasons.
As proof of wool's durability, the Pazyryk rug is close to 2500 years old. It was found in Siberia, basically intact. You can see it in the Hermatage Museum.
Wool lasts!
Indeed there is a vibrant international market for antique rugs (over 100 years old). Collectors buy these not for display or to hang, but to add prestige and luster to their floors.
A well-cared for rug can take a huge amount of traffic.
You know how you can take a piece of wire and bend it back and forth until it breaks. You can do the same thing to a wool fiber and you have to bend it over 10 thousand times before it snaps. In contrast, silk fiber snaps after around 2400 bends.
Nothing comes close to wool for durability.
One of the reasons is that rugs are moisture repelling. For centuries people have stayed warm in wool even when it's wet.
You would not want your rug to stay wet to avoid mildew and other rotting. However, water won't hurt your rug. As a matter of fact it was washed as soon as it came off the loom.
And the way wool can hold dye is a marvel. Its fibers absorb and hold pigment in smooth uniform manner. Working with the way wool tones the dye is the dyemaster's art and is easily seen in any beautiful rug.
Maintenance is easy compared to that of any other material. Simply dab up neutral spills. Pour water through wine spills until you can dab the grape pigment away. See more on wine spills here.
Even dog accidents can be handled at home in most cases. However, sometimes you are going to need a professional to bring your rug back to a brand new state. Cats accidents can be tragic. Read more here.
As a well-cared for rug ages it can become more beautiful. That's because scales on the outside of the wool slough off over time, revealing shiny new fiber underneath. I have heard stories of this process taking away stains over time.