Medical experts generally recommend changing your underwear every day. Throughout the day, underwear collects sweat, natural oils, dead skin cells, and bacteria. Wearing the same pair again the next day gives those microorganisms more time to multiply, especially in the warm, moist environment close to your skin.

For most healthy people, wearing the same pair twice won’t automatically cause an infection. However, making it a regular habit can increase the chances of skin irritation, chafing, unpleasant odors, and bacterial or yeast overgrowth. Moisture and friction can also make sensitive areas uncomfortable.

For women, wearing damp or unclean underwear for extended periods may contribute to an environment that favors yeast overgrowth or irritation, although underwear itself isn’t usually the direct cause of a urinary tract infection. People who sweat heavily, exercise, or live in hot and humid conditions may need to change even more frequently.

The simple rule is easy: fresh underwear every day, especially after sweating or exercising. It takes only a few seconds and helps keep your skin clean, dry, and comfortable. So, be honest—have you ever worn the same pair two days in a row?