I would firstly look at the rug, is there darkness in traffic areas? Are there any spills? Is there a wear mark appearing?
A test for you!
The best way to keep a rug clean is to keep it from getting dirty in the first place. Removing outdoor shoes when entering the house (as people do in most rug-weaving countries) is a good idea if this accords with your lifestyle. Bare-foot or sock-foot traffic is much gentler to a rug than a hard outdoor-shoe sole (or spike heel), and leaving your outdoor shoes at the entrance to the house tracks in much less dirt.
Have your rug cleaned only when it really needs it. For rugs in some areas this will mean a yearly cleaning. Rugs in other areas can go several years and more without needing professional cleaning.
To judge how dirty a rug is, try one of these methods:
- Pick up a corner of the rug and while holding it, kick the back of the rug sharply. If a cloud of dirt flies out of the pile, the rug is dirty and needs cleaning. NOTE: some dust and wool fibers are normal!
- Kneel down on the rug and rub the pile vigorously with your hand in a short arc for 5 to 10 seconds. Look at your fingers and palm: if your hand is dirty, the rug needs cleaning.
- With the pile facing UP fold part of the rug back upon itself so that the pile opens along a line of knots. Look down into the base of the pile at the foundation of the rug. If the warp and weft look dirty, there is dirt deep in the pile where a home vacuum cleaner cannot reach it. The rug needs cleaning.