Two garments can both say one hundred percent cashmere and behave completely differently, because grade depends on fibre length and how many strands are twisted together. Two-ply lasts, single-ply pills within weeks. The best cashmere sweaters are usually the heavier ones. Cashmere went from a luxury signifier to a high-street commodity in about twenty years, which is why the word now tells you almost nothing on its own. Grade did all the work the label used to do.

Some surface pilling in the first few wears is normal as short fibres work loose, and a comb fixes it permanently. Pilling that keeps returning after a month means the fibre is short throughout. That is the honest test of a sweater. Early pilling is short fibre working loose and is entirely normal, which is the opposite of what most buyers assume. Persistent pilling after a month is the real diagnostic.

Cashmere is the undercoat of a goat, combed out once a year across Inner Mongolia and the Tibetan plateau, and a single animal yields a few ounces. That supply constraint is the entire economics of the category and explains why costs have not fallen despite decades of scaling. Demand grew faster than herds could, which pushed mills toward shorter fibres and thinner plies to hold the line. The result is that a sweater today can be genuine cashmere and still be a fraction of the garment it would have been in the 1990s. Grade, not the word on the label, is what you are choosing between.

Ply counts the strands twisted into a single yarn and gauge counts the stitches per inch, and together they decide how a cashmere piece wears. Two-ply is the sensible default because a single ply stretches out at the elbows within a season. A tighter gauge feels denser and holds its shape while a loose one drapes and pills faster. Hold a sweater up to the light, and if you can see through it clearly it is thin rather than fine. Weight in the hand is a rough but reliable proxy for both.

Wash cashmere yourself in cool water rather than sending it out, and lay it flat. Dry cleaning solvents strip the oils that keep the fibre soft. One good sweater outlives four mediocre ones. Dry cleaning strips the oils that make cashmere feel like cashmere, which is a genuinely counterintuitive result. Cool water and a flat surface outperform a professional every time.