Keeping the clunker - what it costs and when to let go

Consumer Reports a couple years ago calculated that you could basically save the price of a new car by driving your old one longer -- 15 years and 200,000 miles.

Lord knows, I've tried. Ms. KTnomics, who took the Vespa to work today, and I have had two vehicles in our lives that we've pushed to within an oil change of 150,000 miles. Thieves stole and wrecked our '85 Jeep Wagoneer, which easily would have made 200K or more otherwise. The '96 Saturn just wore out.

You learn a lot keeping a car that long. Regular maintenance is critical, of course. But you also find yourself prioritizing maintenance and repair as time passes. Edmunds.com outlines the priorities succinctly here. Your first money pays for safety- your own or others. Next you spend what you need to avoid breaking down. Keeping the car running comes after that.

Where you save money is obvious. There are no more car payments when your loan is paid off. Your property taxes, licensing fees and insurance costs drop when your car gets older. On the flip side, you'll probably make some major decisions about repairs as time passes too.

People who are better with wrenches than I am say repairing generally is more economical than replacing for the first decade or so. But think hard and do the math when Kelly, Edmunds or comparisons on Autotrader.com estimate your car's value is approaching the $2,000 or $3,000 range or its mileage nears 150,000. You can do a lot of the work yourself, but remember that many of the jobs may not be as fast or easy as the instructions say.

The cash for clunkers plan to stimulate car sales adds a new calculation to the works, says CBS News consumer reporter Ray Martin. The plan's tax credit for up to $4,500 might offset the depreciation that will occur when you drive your new car off the dealer's lot.

Again, do the math. Come replacement time, buying a good used car may be even more cost efficient.