Wool is a very durable fiber and can withstand over 20,000 bends. In contrast, cotton breaks after 3,000 bends and silk after 2,000 bends.
Wool is also a long-wearing fiber that maintains a good appearance, when given proper care. It is naturally elastic which results in the fibers stretching, rather than breaking, under load. Since the fibers are elastic, they will spring back when the pressure is released. Because of this, wool garments retain their shape and are very resistant to tearing.
Wool can absorb 30% of its weight in moisture. It wicks moisture away from the body, keeping the person warm without the wet and clammy feel of other fabrics such as cotton. Wool maintains 80% of its insulating value, even when saturated. Wringing liquid out of a wool garment, then putting it back on, is an effective strategy if it gets soaked. In extreme weather conditions, this can make all the difference.
Wool functions as a temperature regulator, so it works in both cold and warm climates. That’s why wool is worn throughout the desert regions of the world, as well as the colder regions.
Depending on the sensitivity of a person's skin and the micron count of the wool, it can sometimes irritate. Research shows that most fibers greater than 30 microns in diameter are structurally rigid enough that, when they come into contact with your skin, do not bend. That "poking" can bother a person. For a garment to be worn next to the skin, no more than 5% of the wool fibers should be greater than 30 microns. The majority of wool yarns today are soft enough to be comfortable, even to very sensitive skin.
Wool is naturally flame retardant. In clothing, it will not melt into the skin like many fabrics, making it wonderful for baby blankets and clothing items. When exposed to flame, it chars or smolders but it does not burn. This is why wool blankets have been traditionally recommended for use in extinguishing fires.