There's more to the equation than what your future repair bills will be. Consider all your estimated costs to replace worn parts vs payments with warrantee and value at the end of 5 years and I bet the new or newer truck comes out on top. Top dollar is being offered for 250/2500 and 350/3500 trucks to private buyers. It took me one week to sell my 2005 (200K miles)for nearly 50% what I paid for my 2014. Of course if you are not able to do most repairs yourself the balance is even more one sided. Those repair bills really dig into the pocket 1200 miles from home with no warrantee.