The twenty-wash test: what happened to the pairs
We washed five pairs 20 times and compared: how cotton, merino and blends behave after serious wear.
Experiment conditions
Five pairs: cotton, cotton-polyamide, merino, merino-polyamide and a sports blend. Washed at 30° on a delicate cycle, dried away from the radiator, weighed and measured after every fifth wash.
Cotton: predictable
Pure cotton noticeably shrank and became stiffer after 20 washes. The shape remained, but the elastic grip weakened - the pair began to slip.
Cotton-polyamide: almost like new
The best result among the cottons: minimal shrinkage, shape in place, elastic alive. Polyamide is the main ally of durability.
Merino: a miracle, but with a nuance
Merino stayed soft and warm after 20 washes. Pure merino lost its shape slightly, merino-polyamide did not. Neither faded nor shrank.
Sports blend: the leader
The synthetics barely changed: colour, shape, elasticity - all in place. The only downside is the odour with repeated use without washing, but that is a hygiene matter.
The result
20 washes is about a year of wear. If you want a pair for several seasons, look for at least 30% polyamide in the composition. Pure cotton and pure merino are for those ready to change pairs more often.