In some instances, normal characteristics of carpet may be mistaken for manufacturing defects. Examples of conditions that are not manufacturing defects and occur routinely. Consumers should contact the company who's delivered the carpet for a more complete description of these carpet characteristics if not explained yet. As there are quite a couple of points to be explained, it's split into parts to write about.
Carpet appearance can change gradually after it is placed into service. Appearance changes have nothing to do with wear warranties. Appearance can be affected by foot traffic, soiling, staining, sunlight, moisture, and other environmental influences.
All carpet will crush to some degree. Crushing is influenced by traffic level and maintenance. Regular vacuuming and regular cleaning can reduce the degree of crushing that will occur.
Filtration soiling may appear as dark or greyish lines on carpet along the walls, under doors, around vents, or on stairs. It is caused by airflow over and through the carpet that allows fine soil particles to collect on the carpet surface. Filtration soiling often can be attributed to an improperly balanced ventilation system.
... to be continued