I have a truck...in fact we have several that we use on the farm and for other work. I was driving a 1997 F150 V-6, ran that truck well over 300,000 miles between 1999 and 2006. It was replaced by a extremely low mileage 1996 F350 diesel, that truck currently has ~138,000 miles on it. It has shed ~ 1/3 of it's purchase value in the past 3 years. It is currently for sale because I don't seen a need for in the future. I saw a similar 2003 truck with ~150,000 miles on it currently listed for less than half of the original sticker price.
My philosophy is to buy good, clean, used (not always easy with trucks) and run them until the wheels fall off, about the same way I do my bicycles. However my mechanical things do not get abused, they get used and properly maintained. If something isn't being used, it gets sold...except bicycles.
Aaron