Sand is to carpet what saws are to trees. I own a carpet cleaning company in the Minneapolis – St. Paul Area and Minnesotans track a lot of sand onto our carpet. Carpet fibers are very thin strands; thinner than the hair on you head. The fibers are woven and spun together for strength in numbers. This is why we can walk on carpet without damaging it much while the carpet is clean. The fibers rub against other fibers with limited friction.
Sand, on the other hand, has at least two ways of changing this. These tiny grains of sand are like boulders to the tiny thin carpet fibers. The sharp surfaces of the sand are more than enough to chop through a few individual fibers. Another instance is when two pieces of sand rub together with a few fibers in between them. Eventually they rub right through those fibers. This is like having sandpaper taped to the bottom of your shoes.
If this is your home then it is not too hard to have people take off their shoes. This will cut down on the need to have the carpet cleaned as often. In businesses, you can’t ask people to take their shoes off. You can, however, have the carpets cleaned and protected on a consistent schedule that make sense for the volume of traffic your company receives. The cleaning removes the sand and the protector coats the fibers and makes them thicker for the sand attacks that happen in between the cleanings.