I wear mine until they start to smell, then I stop. Or if they are visbly dirty, then I stop too. Last week I found a shirt in my closet that I hadn't worn and forgot to clean for over a year. It had these nasty yellow stains all over the collar. I took it to the dry cleaner thinking it probably wouldn't come out. But after I got it drycleaned then it came back looking good as new. The yellow stains were completely gone.