I should probably wash mine more than I do. I have three underworks double fronts that I wear, two primaries with one backup just in case. Every couple days, or whenever I feel like it, I swap out. I wash them when they start to smell or get dirty. I put them in the dryer on delicate for about 15 minutes then hang them up to air dry. If I need to freshen one up quickly, I'll stick it in the dryer on delicate with a dryer sheet for 5-10 minutes. They've held up pretty well.