There are several factors involved in the making of a high-quality cashmere garment. As well as the quality and source of the wool itself, there is the strength of the thread, the thread count, and the number of plies.
Each strand of wool varies in thickness from one end of it to the other, in a random fashion. Therefore, each thread is made up of two strands woven together, so that a thin area on one is compensated for by the thicker part of the second thread. This is standard throughout the industry, so the reliability of thread strength is quite stable.
The thread count is the number of threads found per square inch of the garment. A tighter weave means more threads, which means a higher thread count. This is considered a major marker for a high-quality product.
By far, the most popular number of plies is two. This creates a fairly light fabric, but one that is still durable and warm. It can be worn as an outer garment in warmer weather, but also functions well beneath a windcheater, keeping the wearer warm and cozy in colder spring or autumn weather.
A garment with more than two plies is not necessarily of a higher quality than a two-ply garment, but it will be heavier, considerably warmer, and considerably more expensive, as it uses more wool than a two-ply. Because it is thicker, it will be more durable as well.