Hi,
I got some inspiration for this question from another thread where people discussed how long they would keep their Liberty CRDs. Most said they would basically keep it until it falls apart (hopefully many years ahead).
Since I live in Sweden I don't know what it costs to own older, diesel cars in the US, but this leads me to believe that it's not that expensive. I am talking road tax and insurance here. In Sweden, it IS expensive, since our government wants us to own newer and fuel efficient cars (and preferrably fewer cars overall) and punish cars like older Liberty CRDs. So it's not a clear case to hold on to one's Jeep forever.
I'd love to know what these costs would be for you guys in the US. I own a '02 stock CRD and this is what it costs me just standing still (and I am a low-risk customer):
Road tax: US$ 80/month (my other car, a modern, powerful '11 Volvo XC70 AWD Diesel, costs about US$ 60/month. A typical, smaller gas powered car, maybe US$ 20/month)
Full insurance: US$ 70/month (my new Volvo about the same)
Oh, and the fuel: gas and diesel costs about the same per gallon over here, about US$ 8.20 per gallon. I'm glad diesel cars at least get better MPG...

How expensive/cheap are these things for you?