You need to separate the combines sold to farmers, and those to custom cutters. I heard once that 70% of all new combine sales are to custom cutters. I don't know if its true, but judging by the number of used 2-3 year old combines in the country, its probably close. If you look at it from the custom cutter perspective, new is the only way to go if they can afford it. They don't have unexpected maintenance costs- most run the machines through the warranty period (two or three years)and then trade off. Easier to budget, plus financing terms on new stuff is usually better than used. New machines are typically more reliable, which is important since time is money to them. If a machine sits a few hours, the owner loses more money in lost opportunity costs and labor than the repair itself. A new machine also has the added benefit of attracting potential customers- the guy with new iron looks more successful and capable of delivering the work than somebody running older stuff. The bottom line is that custom combining is not farming- its an ag service business. More similar to construction in the management of labor and equipment costs- most important thing is not the cost of the wheels, but to keep them turning.