Quick Answer: Check fibre, underarms, and cuffs - in that order, and it takes under a minute. Read the label first: wool, cashmere, lambswool, and alpaca are worth the effort; acrylic almost never is at any price. Then check the underarms and inner elbows for thinning by holding them to the light, and stretch the cuffs and hem to see whether the ribbing returns. Pilling is fixable, small holes are fixable, thinning fabric and dead ribbing are not - which is the whole distinction between a bargain and a waste.

Here is the full check, in order.

What should you check first, and why?

The label, because it decides whether the rest is worth doing. Wool, merino, lambswool, cashmere, alpaca, or a blend above about 50 percent is worth inspecting; a 100 percent acrylic jumper rarely is.

Fibre determines how it ages, not how it looks today. Acrylic pills permanently and holds odour, while wool sheds pills, resists odour, and can be restored - which is why a used wool jumper often beats a new synthetic one.

No label is not a dealbreaker. Rub a small area between your fingers - wool feels slightly springy and warms up, acrylic stays cool and slightly squeaky.

Check the country and era of the label too. Older knitwear is frequently better made - fully fashioned shoulders, heavier gauge, and real ribbing rather than a rolled edge.

And weigh it in your hand. Density is the single best proxy for quality in knitwear, and it is immediately obvious once you have compared two.

Which faults are fixable and which are not?

Pilling is fixable and should not put you off. A fabric shaver or a comb takes ten minutes and removes it completely, and pilling on wool stops after the first few de-pillings.

Small moth holes are fixable. A hole up to about 5mm can be closed by a mender or a competent home repair, and it is worth doing on good fibre.

Odour is usually fixable. Airing outdoors for two days, then a wool wash, removes almost everything - the exception is smoke, which is genuinely persistent.

Thinning fabric is not fixable. Hold the underarm and inner elbow to the light - if you can see through it, the jumper is at the end of its life regardless of how it looks folded.

Dead ribbing is not fixable. Stretch the cuff and hem and let go. If it does not return, the elastic recovery is gone, and the jumper will sit badly forever.

And felted or shrunk wool is not recoverable. A dense, stiff, slightly matted texture means it has been washed hot. It will never soften again.

How do you check fit on knitwear you cannot try on?

Measure across the chest flat and double it. Compare against a jumper you own - this is far more reliable than the size label, which varies wildly across eras and countries.

Check the shoulder seam position. Fully fashioned shoulders sit at your shoulder point; drop shoulders are meant to sit past it. Knowing which the garment intends prevents buying something that only looks too big.

Sleeve length matters more than body length in knitwear. A sleeve past the knuckles can be pushed up; a sleeve short of the wrist bone cannot be fixed.

Look at how it hangs on the hanger. A jumper that hangs straight and square has kept its shape; one that hangs with a twist or a droop at the hem has not.

And check the neckline recovery. A stretched-out crew neck is the most common irreversible fault, and it is easy to miss when the jumper is folded on a table.

5 Mistakes Everyone Makes Thrifting Knitwear

1. Judging by how it looks folded. Almost every fault is invisible folded. Unfold it, hold it up, and hold the underarms to the light.

2. Buying acrylic because it is cheap. It is cheap new too. The value in secondhand knitwear is in fibres you would not otherwise buy - wool, cashmere, alpaca.

3. Ignoring the cuffs. Dead ribbing is unfixable and immediately obvious once worn, and it is the fault people skip most often.

4. Being put off by pilling. Pilling is the most fixable fault there is and it is the reason a good jumper is on the rail for a low price at all.

5. Not checking the underarm. This is where knitwear wears out first, and a thin underarm means the garment has weeks rather than years left in it.

FAQ: Thrifting Knitwear, Answered

How do I know if a secondhand jumper is worth buying?

Check the fibre on the label, hold the underarms and elbows to the light for thinning, and stretch the cuffs to see if the ribbing returns. That covers most of the risk in under a minute.

Is pilling a reason to walk away?

No - it is the most fixable fault and often the reason a good jumper is cheap. A fabric shaver removes it in about ten minutes.

What cannot be repaired?

Thinning fabric, dead ribbing, and felted or shrunk wool. All three are permanent, and all three are easy to check for.

How do I tell wool from acrylic without a label?

Rub a small area between your fingers. Wool feels springy and warms slightly; acrylic stays cool and can feel faintly squeaky. Weight is also a good clue - wool is denser.

How do I get the charity shop smell out?

Air it outdoors for two days, then wash it in a wool detergent on a cool cycle. Smoke is the only odour that reliably persists.

Should I trust the size label?

No. Measure the chest flat and compare it against a jumper you already own - sizing varies enormously across decades and countries.

TL;DR:

• Label, underarms, cuffs - in that order, under a minute.
• Wool, lambswool, cashmere, alpaca are worth it. Acrylic almost never is.
• Fixable: pilling, small holes, odour. Not fixable: thinning fabric, dead ribbing, felted wool.
• Hold the underarm to the light. That is where knitwear dies first.
• Stretch the cuff and let go. No return means no recovery, ever.
• Measure the chest flat and compare to a jumper you own - ignore the size label.
• Never judge it folded. Every real fault is invisible that way.

Pilling is why good jumpers are cheap. That is the whole opportunity.