This is one of the most common questions I’m asked. I know that when you bought your rug you were probably told that rugs (especially wool rugs) don’t need to be cleaned very often because of their quality. Well, wool rugs can hide soil much better than wall to wall carpet, or even synthetic rugs. However, the scales or cuticles on wool fibers can get so filled with dry soil (even with regular vacuuming) that they will start to break off from the weight of this trapped soil.
Rugs that live in your entryway or hall runners or in any room where you watch television or read should be cleaned annually. Rugs that are in seldom used rooms (in my home that would be the formal dining and formal living and study) will normally be fine with every other year, IF you implement my recommendations on making your rugs last longer.
Rugs that live with pets should be washed annually. If you suffer from allergies, annual cleaning is strongly recommended. Remember that your rug is a filter that traps millions of airborne particles that move through your home every minute of every day. It needs to be unplugged to continue to work well in your home. Imagine how much harder your air conditioner has to work with a clogged filter or how long your car would last without changing the oil for years.
I do not sell rugs, so I want your favorite rugs to last as long as they are able. Waiting until your rug is visibly dirty is poor advice. I know the stories about how rugs are often used as floors in overseas villages, so they require little care. Hygiene alone would require a more thorough and frequent rug cleaning schedule for your rugs.