I only use mine for RV pulling mainly, so the 03 is only at 112K miles. Still reliable and runs good. I just replace the aged out stuff as needed. I try not to drive the newer trucks though, I don't want to know what I'm missing!
I figure ball joints will be coming up soon, but so far they are original. The truck has been mostly trouble free. Couple water pumps, auto trans rebuild and an injector line. Wiring harness replaced under warranty. Interior is still clean, the dash is cracking under the mat I added years ago. It has a dash rattle at idle, it has been wrecked once, drivers side fender and mirror, hit a flying mattress on the interstate. Its been my favorite truck ever though. My Fords had much more issues, but that was in the 90's. If you keep them 6 years or longer they drop so much in value in normal markets, normal times. Banks won't loan on older trucks much either.
65K miles is a no brainier for me. I would keep it, but I hate truck payments! I only pay $20 something in registration tag fees. Insurance is cheap too. I guess as longs as the parts are available I'll keep mine running. I still have my 1995, the biggest expense is insurance. When I'm not using it i just park it out back as a back up "farm truck" since its more useful around the property than buying a golf cart or some side by side.