You might faind that your cotton t-shirt or jeans create more problems if you begin to sweat a bit. I find that staying WARM when I am hiking is the least of my worries. The real worry is staying warm once I STOP hiking. And since my body is creating heat while I am hiking, if I sweat a bit (quite possible, even in very cold temps) then that cotton t-shirt or jeans get wet---ands stay wet. Two hours later, standing around in camp, it would be freezing.

The real test for all this stuff is to go for a hike for 7 miles...then stand around in tne backyard for three hours watching your pot boil, etc.

In that scenario, you will really understand why synthetic wicking material is so popular...and warmer.