Dear Car Talk:

I am a senior citizen, and I drive a 2005 Toyota Matrix with 100,000 miles on it. It is time for routine maintenance, and I need to know just what parts of the car are critical to replace with this amount of mileage. I trust my mechanic, but I live on a restricted income and do not want to spend money on work that might not need to be done. I have never had to spend large amounts on this car in the 11 years I've owned it. I replaced the tires and the front brakes at 90,000 miles. In your opinion, what should I have the mechanic check and possibly replace? I appreciate any advice you can give me.

-- Lillian

You can find a lot of those answers in your owner's manual, Lillian. There are scheduled maintenance "services" called for at certain mileage intervals. Your Matrix calls for oil and filter changes every 5,000 miles, with "major services" every 15,000 miles.

So your last major service should have been at 90,000 miles. You'll find a list of all of the things that should have been checked and/or changed during that 90,000-mile service in the maintenance section, toward the back of your owner's manual.

If your mechanic already did your 90,000-mile service when you had the tires and brakes done, you shouldn't need much of anything right now, other than your oil and filter change. At 100,000 miles, you're supposed to change the coolant, and I'd recommend that.

If your guy didn't do the 90,000-mile service for you, then you'll want to go back and see what you missed. For instance, at 90,000 miles an air filter is recommended. And, more importantly, Toyota recommends tightening the drive-shaft bolt, which I guess tends to loosen up on this car.

Other than that, because this car is now a senior citizen, too, your mechanic should check all of the things that are safety-related. Obviously, your tires and front brakes should be fine.

But he'll check your struts and steering components, and make sure the car is safe to drive.

Then there are things that simply wear out over time, like your exhaust system or your fuzzy dice. If you trust your mechanic to be honest with you, and he respects your financial situation, then you should take his word for it if he says something like that needs to be done.

But if you want to bone up in advance, before going to see him, you'll find a list of recommended maintenance items for the 90,000- and 100,000-mile services in your owner's manual. And you'll find that at the bottom of your glove compartment, Lillian, right under that Starbucks Mint Frappuccino coupon that expired in January 2006.