I don't look forward to the day retiring our 2006 Jeep Liberty 4x4. Though I have my reasons to dislike it, it has met our RV travel and Irene's at-home needs. We'll keep it for as long as is reasonable. It recently turned 80,000 miles. Given it's care and condition, I hope replacing it is 10 years away. It's just a year older than our PC but at a much faster pace to retirement.
It seems brand new towable 4x4 vehicles are quite pricey, especially after being setup properly for towing. The way it's heading, when we replace our Liberty, a new tow vehicle will cost more than our PC did in 2007.