The best cashmere sweater is the one you stop thinking about. It goes on over everything, it holds its shape by the third wash, and it does not pill into something you are embarrassed to wear to work. That is a low bar and most knitwear fails it, which is why I spend more time on this category than almost any other.

What I look for is boring and it works. Weight first: a two ply cashmere at around 12 gauge feels like a real sweater rather than a whisper, and it survives being pushed up your forearms all day. Then the seams, because a fully fashioned shoulder means the panels were knitted to shape instead of cut out of a sheet of fabric, and cut edges are where knitwear starts to go. Then the ribbing at the cuff and hem, which should spring back when you pull it. Fibre length matters more than the word cashmere on the label, and the honest signal is price against feel. A $250 cashmere sweater exists and some of them are good, but the ones that stay good for a decade tend to sit higher.

I also stopped treating cashmere as a single thing. Merino handles daily wear better under a coat, alpaca gives you loft without weight, and a cashmere silk blend drapes in a way pure cashmere does not. So this issue is not purist. It is forty knits across sweaters, cardigans and the wool family, all from Net-A-Porter, all in stock as I write.

Below, the pieces I would put my own money on, starting with the label that owns this category.

The Row is the reason the plain crewneck became a fashion object again, and I am not going to pretend otherwise. What you are paying for is gauge and proportion. The Pato and the Sibem sit slightly away from the body so the sweater reads as a shape rather than a layer, the Kensigton turtleneck has a neck that actually stands up, and the Pranavi cardigan is cut long enough to work as outerwear indoors. The Nile cashmere silk and linen blend is the one I reach for in a transitional month, because it has the hand of cashmere without the heat. Prices here run from around $890 to $3,100, which is a lot, and I would rather own one of these than four of something else.

This is the working grid. Loulou de Saison's Derry is the cleanest plain crewneck in the group and the one I would buy first. Khaite's Gemma is heavier and holds a boxier line, Allude's cashmere and silk blend is the drapey option, and La Ligne's Ben brings a silk wool cashmere blend in at $250, which is the value pick of the whole issue. Ralph Lauren Collection's cable knit is the traditionalist choice and Gabriela Hearst's Chryse mixes cashmere silk and hemp, which sounds odd and wears beautifully. Note how many of these are blends. That is not a compromise, it is usually a better sweater.

A cardigan does something a pullover cannot, which is open. Toteme's Jersey is the disciplined one, cut close enough to wear buttoned as a top. Nili Lotan's Lorana is the wool and cashmere blend I would pack. Leset's pointelle knit cotton jersey is $120 and the only piece here I would call a genuine bargain. Then the ones with a point of view: Alémais's mohair and alpaca with beaded appliques, Altuzarra's argyle, Zimmermann's ribbed knit with a leather trimmed collar, and Staud's Marianne, which is crepe and reads much more expensive than $245.

Cashmere is not always the answer. Merino is the fibre I actually wear under a coat because it takes friction without fuzzing, and Our Legacy's Dash zip up cardigan is the piece I would live in. &Daughter's Sligo and Innes are Irish and Scottish spun wool, dense and slightly rustic in the best way. The Frankie Shop's Sade is a ribbed wool and silk half zip, Valentino Garavani's cable knit is the show off, and Zimmermann's Valiant turtleneck has lace trim that keeps it from reading like a base layer. Versace's Gianni is the loudest thing in this issue and I put it in on purpose.

Eight more I did not want to leave out, spread across price and weight. Use this grid as the overflow: a black crewneck if you need the neutral, a pale pink if you have enough black, a striped wool if you want the sweater to be the outfit, and a cropped shape if you wear things over high waisted trousers. Everything here links straight through to Net-A-Porter.

A last thought on care, because it decides whether any of this was worth it. Wash cashmere yourself in cool water with a wool detergent, press the water out instead of wringing, and dry it flat. Dry cleaning solvent strips the oils that make the fibre feel like cashmere in the first place, so save it for the structured pieces. Fold, never hang, and buy a cheap fabric shaver rather than picking at pills with your fingers, which pulls the yarn.

If you are starting from nothing, my order is a mid weight crewneck in a colour you wear every week, then a cardigan, then the turtleneck. That is three pieces and it covers about nine months of the year. I would spend the most on the first one.

Phoebe