A three-year reliability study by J.D. Power finds cars are the most dependable they've ever been, no matter whether you're talking about domestic or import vehicles.

Top brand honors in the survey that looks back at 2010 nameplates go to Lexus, followed by Porsche, Lincoln and Mercedes Benz. Tying with Lincoln was Toyota, the only non-luxury nameplate at the top.

This survey is particularly important if you're interested in buying a three or four year old used car.

On the other end of the scale, the survey identified some real laggards with little reliability. They are Dodge, Jeep, Land Rover, and Mitsubishi.

Overall, the good news is cars are now the most dependable they've been in a generation since J.D. Power started tracking in 1990.

The reality is that the car market is so competitive that manufacturers have to churn out good cars just to survive. There are so many cars available with a price tag of the mid teens to high teens that are better than a fancy car was 20 years ago. Cars made today are much safer and get much better fuel economy.

Now, the inevitable question, since newer cars are so reliable, so should you buy a new car before you need one? Well, if you have great wealth and no debts in your life, then I say it's fine. But if you just paid off your old car, I suggest that you keep driving it until the wheels fall off.

Too many people ditch cars because they're bored with them. That's the wrong reason to get out of a car. Do it only when it comes time in your natural buying cycle when your old wheels are well past the point of repair.