>>2463473Because cotton is far, far comfier than any other fabric next to my skin. I use synthetics for outer layers but my under layers are (mostly) cotton.
It's not ALWAYS 4 changes of shirts - usually it's just one or two, especially uphill obviously you just need one extra t-shirt and then you change into that at the summit and then have another back at the car if needed. Depends on the weather too.
