You might think of yourself as a laundry pro — you're at the laundromat every other week, cleaning everything from your sheets to your workout clothes. You know how often to wash your bras , and how to treat pit stains . But what about the common household items that you rarely think about cleaning (until they smell weird)?Plenty of non-clothing items can (and should!) go in the washing machine. Shower curtains, dish towels, bath mats — they all get dirty over time. But how long, exactly, can we get away with using these items before they need a refresh?To learn more about just how often you should really be cleaning, we talked to Mary Zeitler, a laundry expert at Whirlpool Corporation's Institute of Home Science. The good news is that some items, like duvets, might need to be washed less often than you think. But if, say, your bed sheets are on a monthly washing schedule, it's time to up your game.Click through to see just how often you should really throw common home items in the washing machine — you'll never second-guess what to wash on laundry day again.