The British Army has underwear that you can wear for 3 months at a time!
When you think of the travails of war, you think of the life and death situations and the violence. You don't often think of the unsanitary conditions and the day-to-day discomforts of being a soldier. The British Army does think about these things though.
In 2005, the British Ministry of Defense issued British soldiers antimicrobial underwear. The unisex undergarments were made from artificial fibers and laced with silver to help prevent sweating. It is also coated to prevent bacterial infection and the seams were strategically placed to prevent sweating.