Q: I am in the market for a safe, fuel-efficient, inexpensive car for my daughter who is in college in Tucson, Ariz. I am seriously considering the Chevy Cobalt as it is so attractively priced right now. Is this a good choice? Or, should I consider something else?
--Donna Hellwinkel
Reno, Nev.

The Mazda3 5-Door Mazda

A: I think you should consider something else. It isn't that the Cobalt is a terrible car. Indeed, I know people who are fond of their Cobalts. But I think there are better-built, better-performing compact cars that are also worth your consideration. These include the Mazda3, Ford Focus, Subaru Impreza and Volkswagen Golf and Jetta. I think you should test drive as many of these as possible to see which you find the most satisfying. If you decide to stick with Chevrolet, there is a newer version of the Cobalt called the XFE that is particularly fuel efficient and worth a look.

Q: Honda does not provide any maintenance schedule to replace the power steering fluid in my 2003 Odyssey. Nor does it give any tell-tale signs to look for if the system is not working properly.

I am nervous that in 75,000-plus miles, I have never changed it. Does Honda expect owners to never change the fluid? Is this a lifelong fluid that doesn't wear out or get contaminated over time? Or is it an opportunity for dealers to sell us on expensive flush-and-fill power steering fluid service?
--Chris Castaic
Seattle, Wash.

A: There are many carmakers who claim that certain fluids will last for the lifetime of their vehicles. In some cases even transmissions are filled with such "lifetime" fluid. In other cases the manufacturer suggests inspecting the fluid at regular intervals and replacing it only if a potential problem exists.

I think a car's life will be longer if fluids are changed regularly. Even though your van's steering hasn't shown signs of wear, I think you should have the fluid drained and replaced. It's an inexpensive service that will help.

Q: I live in the Texas hill country and typically downshift (automatic transmission) when moving downhill to maintain my speed or to gradually reduce the speed. This increases engine revs to the 3,500 or 4,000 level.

Am I harming the transmission while saving the brakes? Does the increase in engine revs decrease gas mileage? Driving in this manner fits a sporty feeling in driving and the car (BMW) seems to encourage such activity with its shifter arrangement.
--Craig Owen
New Braunfels, Texas

A: You probably are causing a bit of extra wear to your transmission while reducing wear to the brakes. But I don't think the wear is significant. Critics may tell you not to drive this way because it is cheaper to replace brakes than replace a transmission. However, the transmission in your BMW is designed to be shifted manually and used in a sportier manner than the typical automatic.

Using the transmission to control your speed on hills is a good idea in part because doing so nearly guarantees that you are concentrating more closely on your driving and paying attention to the car's behavior on the road.

Q: In June I purchased a new Honda Civic Coupe. I was advised not to take any of the dealer add-ons, which included the undercoating. Now with winter weather approaching and salty roads, I'm having second thoughts. Do you think I should go for the undercoating?
--Bob Pugh
Baltimore, Md.

A: I understand how the thought of harsh winter weather and road salt sticking to your car's underside might make extra undercoating seem like a good idea. But I think you should skip it. Unlike the cars of 20 or 30 years ago, modern vehicles receive coatings and chemical treatments at the factory that are generally more effective than any aftermarket undercoating you are likely to find. And in your case, I'm sure the dealer is just trying to squeeze a few more dollars out of you for something your car doesn't need. Indeed, aftermarket coatings can do more harm than good when sloppily applied.