What makes a knit throw worth keeping for years
A knit throw is one of those purchases where the difference between a good one and a mediocre one is immediately obvious in use but harder to assess from a photograph. The things that matter. Fibre quality, knit tension, weight. Are tactile. Since you can't always handle something before buying it online, it helps to know what to look for in the description.
Fibre type and what it means in practice
Cotton, wool, and linen are the most common fibres for knit throws, and they behave quite differently. Wool is warm and elastic. It drapes well and recovers its shape after being scrunched up on a sofa. Cotton is cooler, heavier, and less elastic, which makes it better for summer use or for people who run warm. Linen is the most breathable but also the stiffest, and it softens slowly over many washes.
Blends are common and can combine useful properties. A cotton-linen blend, for instance, is more breathable than pure cotton and softer than pure linen. The trade-off is that blends are harder to assess from a label alone, because the ratio matters as much as the fibre types.
Knit structure and what it tells you
An open knit. Large loops, visible gaps. Looks dramatic and photographs well, but it catches on things easily and can lose its shape if the yarn isn't resilient. A tighter knit is less photogenic but more practical for everyday use. The best throws for actual use tend to be somewhere in the middle: open enough to breathe, tight enough to hold their structure after washing.
Chunky knits made from thick single-ply yarn are prone to pilling if the yarn is short-staple. Long-staple fibres. Which produce a smoother, stronger yarn. Pill less and wear better over time. This is difficult to assess from a photograph but is usually reflected in the price.
Size and weight
A throw that's described as 130 x 170cm is large enough to cover most adults lying on a sofa. Anything smaller is more accurately a lap blanket. Weight matters too: a throw that's too light won't feel substantial enough to be satisfying, and one that's too heavy becomes a nuisance to wash. For a cotton throw, 800 to 1000 grams is a reasonable range for a piece of that size.
The throws that last are the ones that get used. A throw that's too precious to put on the sofa isn't doing its job.