The 1939 Chevrolet was traded in on a 1942 model just before World War II began. Gilbert was fortunate to have acquired the car when he did, as production stopped with the beginning of the war. This car was eventually traded in on the 1947 Chevrolet.
In that era, automobile engines were considered to be in need of complete overhaul at 20,000 miles, so most people who were able to do so traded for a new one every two or three years. The dealer then overhauled the engine and place the car on the used lot.