The 3.5 Duratec is pretty bulletproof, you should get years and years out of it. I had a 2008 Taurus with the same basic motor and got 175000 miles out of it before required massive suspension work made the car untenable. I have a 2010 Flex Ecoboost which is still going strong. I can still surprise a lot of youngsters with smallish Japanese and Korean boy racers as I get up to speed and then some. For you oil guys, the 2010 still specs 5W-20 according to Ford, but I switched to 0W-30 many years ago. My only mod has been to upgrade the brakes to 2013+ Explorer Sport standard and stainless steel brake lines. I really like the car, 2019 or 2020 will be the last year for the Flex model, Oakville ONT is switching or has already switched to another Ford model.