Quick Answer: Check knitwear in this order: fibre content on the label, moth damage at the underarms and shoulders, pilling at the friction points, the state of the cuffs and hem ribbing, seam integrity, and the shape of the shoulder line. Moth holes and dead ribbing are the two deal-breakers — the first is a hygiene issue for your whole wardrobe and the second cannot be fixed. Pilling, minor stretching, and a stale smell are all recoverable, which is where the value is.

Good wool outlives several owners. Knowing which four minutes of checking to do is what separates a bargain from a mistake.

Why is knitwear the best category in a charity shop?

Because good wool is expensive new, holds up for decades, and is priced secondhand by garment type rather than by fibre.

A cashmere sweater and an acrylic one look similar on a rail and are usually priced within a couple of pounds of each other. The entire skill is telling them apart, and that skill is worth more in the knitwear section than anywhere else in the shop.

There is a second reason. Knitwear is forgiving about fit in a way that tailoring is not — a sweater that is slightly large reads as intentional, and one slightly small can often be blocked out. So the sizing gamble that makes secondhand tailoring risky barely applies here.

And a third: wool improves with age up to a point. A wool or cashmere sweater that has been washed a few times has softened and settled, and it often feels better than the new version of itself.

The catch is that knitwear also fails in ways that are invisible at a glance and irreversible once you get home. Which is what the checks are for.

Check one and two: fibre content, then moth damage

Read the label first, because it determines how much the rest of the checking is worth.

Look for wool, merino, lambswool, cashmere, alpaca, mohair, or cotton. Blends with a majority of natural fibre are usually good value; anything above about half acrylic will pill immediately and hold odour.

No label is not automatically a no. Rub the fabric between your fingers — wool has a slight spring and a dry, warm feel; acrylic feels smooth, slightly slippery, and squeaks faintly when compressed. Wool also recovers from a squeeze; acrylic stays creased for a moment.

Then check for moths, which is the check you do not skip.

Hold the sweater up to the light. Moth damage appears as small round holes, usually clustered, and it concentrates in specific places: the underarms, across the shoulders, near the collar, and anywhere a stain would have been. Moth larvae feed where there is body oil and residue.

A single small hole in an otherwise good sweater is repairable. Clustered holes mean an active or recent infestation and you should put it down — not because the sweater is unsalvageable, but because eggs travel and one sweater is not worth risking the rest of your knitwear.

Check three and four: pilling and the ribbing

Pilling is the check people over-weight. It looks bad and it is almost entirely fixable.

Pills form where fabric rubs — the underarms, the sides where a bag strap sits, the front where you lean against a desk. A fabric shaver or a sweater comb removes them in about ten minutes and the sweater looks close to new.

What matters is what is underneath. Part the pilling with your fingers and look at the knit itself. If the fabric beneath is intact, shave it and enjoy it. If the surface has gone thin and slightly transparent under the pills, the fibre is worn through and shaving will make it worse.

Ribbing is the check people under-weight, and it is the real deal-breaker.

Stretch the cuff and the hem ribbing gently and let go. Good ribbing snaps back. Ribbing that stays stretched is finished — the elastic recovery of the knit is gone and no wash, block, or repair brings it back.

This matters because dead cuffs and a dead hem make a sweater look tired regardless of how good the rest of it is. It is the single most reliable signal of a sweater at the end of its life, and it takes three seconds to test.

Check five and six: seams and shoulder line

Turn it inside out and look at the seams. You are checking two things.

First, whether the seams are intact — small openings at the underarm or where the sleeve joins the body are common and are a genuinely easy repair, so they are not a reason to walk away if the rest is good.

Second, how the sweater was made. Fully fashioned knitwear, where the pieces were knitted to shape and joined, has a neat flat join. Cut-and-sew knitwear, where panels were cut from a knitted length and overlocked, has a bulky serged edge. Fully fashioned is meaningfully better quality and it is a reliable signal even when the label has gone.

Then check the shoulder line. Lay the sweater flat. The shoulder seam should be straight and the two sides should match. A shoulder that has stretched into a droop from being on a hanger for years does not recover fully, and it is the reason a lot of otherwise good secondhand sweaters never look right on.

A related check: look at the neckline. A stretched, wavy neckline is the same problem as dead ribbing and it is equally permanent. Both are hanger damage, which is why good knitwear is folded rather than hung.

What Nobody Tells You About Secondhand Knitwear

Wash everything before it enters your wardrobe, without exception. Not for cleanliness — for moth eggs. A gentle hand wash or a wool cycle kills them, and so does 48 hours in a sealed bag in the freezer, which is the right answer for anything too delicate to wash immediately.

Smell is almost always recoverable. A stale charity-shop smell comes from storage, not from damage. A wool wash and a full air-dry outdoors removes nearly all of it, and a second wash removes the rest.

Sizing labels on old knitwear are close to meaningless. Sizing has drifted substantially over decades and knitwear stretches and shrinks over its life. Measure across the chest with your hands and compare to a sweater you own.

Men’s knitwear is systematically better value. It is often better made, less picked over, and the boxier cut is currently the more useful silhouette anyway.

Blocking fixes more than people expect. A sweater that has gone slightly out of shape can be washed, laid flat, and gently pushed back into its correct dimensions while damp. This genuinely works on wool and cashmere and does nothing at all on acrylic.

A hole in a seam is a five-minute repair. A hole in the middle of a knit panel is not. That distinction is worth more than any other single piece of knowledge in this section.

FAQ: Thrifting Knitwear Questions, Answered

How do I tell cashmere from a soft merino?

Cashmere has shorter, finer fibres and a faint halo when you look at it against the light, and it feels warm rather than cool to the touch. Merino is smoother and slightly cooler. In practice a good merino is often the better buy anyway, since it wears longer.

Is one moth hole really worth walking away from?

One isolated hole, no. Several clustered holes, yes — treat that as evidence of a recent infestation rather than as a repair job.

What is the fastest way to check for moths in a busy shop?

Hold it up to the nearest light source and look through the shoulders and underarms. Ten seconds, and it catches nearly everything.

Can I fix a stretched-out cuff?

Not reliably. A hot wash can shrink it slightly, which sometimes helps and often shrinks the whole sweater unevenly. Treat dead ribbing as permanent.

How much is worth paying for secondhand cashmere?

Any price where you would happily wear it as a wool sweater. If the piece only makes sense at that price because it is cashmere, the fibre is doing the persuading rather than the garment.

TL;DR:

• Check in order: fibre, moths, pilling, ribbing, seams, shoulder line — about four minutes total.
• Moth holes in clusters and dead ribbing are the two deal-breakers; both are effectively unfixable.
• Pilling, stale smell, and slight distortion are all recoverable — that is where the value hides.
• Wash or freeze everything before it joins your wardrobe, no exceptions, because of moth eggs.
• Fully fashioned seams and men’s sections are the two most reliable value signals in any shop.

Knitwear is the one category where secondhand routinely beats new at the same price. It just asks for four minutes of attention in exchange, which is a fair trade for a sweater that will outlast most things you buy this year.