We bought the truck used in February, with 86,000 on it. So 14k in 8 months.
Traded in my old truck which I bought new with 4 miles on it, a 2012... we traded it in February with 46,000 on it.
Funny thing is... we pulled in to the dealer in OH, with the 2012 2500 towing a 9,000lb (empty) trailer.. traded in for the 2011 3500, hitched up to the 9000lb trailer... drove another 600 miles west... bought a bigger trailer, 10,000lbs empty, and towed back 1100 miles home (in a nor easter no less)...
I calculated we towed about 8,000 miles this year, either the horse trailer or the boat. This truck is paying its way being safer to tow with (and more importantly stop), but also getting better fuel mileage (old truck got 6-7mpg towing the big trailer, this one gets 10-11mpg).