A clutch might be designed to last a lifetime, but they don't. There was always several things I used to notice in docks and truck stops. Dents on the right side of tractors, busted or missing fairings and the smell of hot clutch. I seen a female driver actually get her clutch so hot it stopped working. Another thing that gets burned out a lot is clutch brakes. Yes I fully agree that a driver should use that clutch until they can float. Floating is when done correctly as you mentioned the easiest on the transmission. To this day I can't understand why some drivers are so hard on clutch brakes. Many years ago I drove a repossessed pete from Atlanta to Dallas bobtail. The clutch brake was burned out in it. Try driving one like that.