This was the first time our 18 month old carpet had been cleaned. While doing the hallway, Scott (the technician) noticed that there was pronounced pooling/pile reversal and pointed this out to me. He found more while doing our living room as well. He pointed these areas out to us and, given that the carpet was less than two years old and still under warranty, we might want to contact the store we purchased it from and/or the carpet manufacturer. This we did. Had he not pointed this defect in material, we might never have known - or at least not until it was no longer under warranty.