"100% ring-spun cotton" turns up on a lot of hangtags, usually with no explanation attached. It is not marketing garnish. It describes how the cotton was turned into thread, and it is the reason two shirts with identical fibre and identical weight can feel nothing alike.

There are two dominant ways to spin cotton, and the choice is almost always about speed.

Two shirts can be the same cotton, the same fibre length and the same weight on the label, and still feel like different garments in the hand.

What separates them is structure. Knitting is a way of building fabric out of loops, and the pattern of those loops decides almost everything about how the finished shirt behaves.

Two shirts. Same weight, same price, same colour. One still looks composed a year in. The other grew a fuzzy halo across the chest by month two.

The difference usually is not the cotton itself. It is what happened to the fibres before anyone spun them into yarn.