If you’re looking at your washing machine and are unable to remember the last time you cleaned it, you might want to get on it. Courtenay Hartford, a cleaning expert and author of The Cleaning Ninja, told Martha Stewart Living you should actually be cleaning your washing machine about once a month. If not, it could not only impact how your machine functions, but also allow debris, soap residue, and minerals from your water to build up in your machine and create the perfect environment for bacterial growth. “Cleaning your washer should be viewed as more of a preventative measure than as something that you do to fix a problem once it arises,” she said. “If you start to notice that clothes come out not smelling as clean as they should, it’s time to clean your machine. You might also notice buildup of various types of debris (pet fur, leaves, etc.) around the seals—that’s a visual cue that you might have forgotten to run a good cleaning cycle for the last few months.” Of course, the laundry room is not the only place in the house people tend to be forgetful with when it comes to cleaning. Read on to find out the other four most common things people don’t remember to wash. RELATED: 40 Percent of People Only Wash This Clothing Item Once a Year, Survey Says. People who can’t remember the last time they cleaned this: 16 percentae0fcc31ae342fd3a1346ebb1f342fcb RELATED: You Should Never Clean Your Toilet With This, Experts Warn. People who can’t remember the last time they cleaned this: 23 percent People who can’t remember the last time they cleaned this: 41 percent RELATED: For more cleaning content delivered straight to your inbox, sign up for our daily newsletter. People who can’t remember the last time they cleaned this: 47 percent RELATED: 1 in 3 People Only Wash These Once a Year, Survey Says.