Have you seen the prices of pre-owned Honda/Toyota sedans that are less than 5 years old? There are absolutely cars out there where trading in your new car after 3-4 years can make sense depending on the cost of the car, the depreciation curve, and whether you want to always be driving a relatively new car. Of course it's almost always going to be a better value proposition to drive the car for 10 years if you can, but that can still depend on depreciation.