Uniqlo Heattech Undershirt

The Uniqlo Heattech undershirt is supposed to retain body heat. I was skeptical until I wore it under a light jacket in 35-degree weather and was actually warm. My issue is that after about 10 washes, the fabric pills noticeably around the armpits and heat retention seems to fade. At $15, it's cheap enough to replace each season. But a product designed around longevity of warmth that doesn't have longevity of material feels like a contradiction. Fit is good, slim without being tight, and the seams are flat so they don't create lines under a dress shirt. I wish they'd offer a $30 version that lasts 2 years instead of making me rebuy the $15 one every fall.