Cotton thermals get heavy when wet and smell like death. Merino regulates temperature, wicks moisture, and stays fresh for weeks.
Why Not Just Buy the Cheap One?
Cotton base layers absorb sweat, become heavy and clingy when damp, and hold odor because bacteria thrive in the moisture. Merino wool wicks moisture away from skin, regulates temperature in both heat and cold, and has natural antimicrobial properties so it genuinely stays fresh for 7-10 wears without washing.
The Buy-Once Math
You'll replace cotton thermals twice yearly at $60 per set; Merino lasts 5+ years with minimal shrinkage. That's $600 in cheap shirts versus $180 in Icebreaker. Plus you stop doing laundry every other day—your time is worth something.