The Sweatproof Undershirt
Credit: Photograph by Greg Broom

You can feel the difference with quality cotton undershirts and boxer-briefs – but unless you're a tax accountant, don't wear a crewneck undershirt beneath an open collar to work. Instead, opt for a V-neck that hides safely under your dress shirt. [Uniqlo Heattech V-Neck, $12.95; uniqlo.com]