Take it easy on the engine, Part I. I advocate buying used cars to save money, but one nice thing about owning a car from the start is that you get to be in charge of the break-in period, the first 1,000 miles or so a car runs. Keeping your speed below 55 mph and avoiding idling for long periods in these critical first miles can help prolong the engine's life. Even afterward, it helps to avoid jackrabbit starts and racing the engine while it's idling. You can reduce wear and tear even more by bunching your errands into fewer trips, because most of the damage done to an engine happens in its first few minutes of operation.

Take it easy on the engine, Part II. Avoid towing or carrying heavy loads. Our Explorer had a tow package, but we used it only a handful of times to pull a trailer with light loads. If something bigger needed moving, we rented a truck. If you do tow heavy stuff, you can try to offset the strain by changing the oil and transmission fluid more often (your owner's manual will offer suggestions), but we'd rather put that kind of stress on someone else's engine.

Be diligent about oil changes. I've been known to go a couple of years without a physical, and I occasionally forget to floss, but I'm pretty conscientious about getting the oil changed. The Explorer manual recommended oil changes every 7,500 miles or six months under normal conditions, or 3,000 miles or three months under "unique driving conditions," such as towing, frequent short trips in freezing weather, stop-and-go driving in hot weather or driving through dust storms.

I don't drive very much -- typically less than 10,000 miles a year. So I wound up changing the oil every spring and fall, rather than waiting for the odometer to rack up enough miles. I also use synthetic oil, which is probably overkill, but it gives me peace of mind.

With every oil change, check the fluids, belts, tire tread and hoses. If you're a do-it-yourselfer, these chores add just a few minutes to the job. If you're paying somebody else, these inspections may be included, or you can pay a few bucks extra to have them done (our mechanic charges $12 for a thorough check).

I have to say I'm not much of a fan of the chain oil-change places; the only time my Explorer ever stranded me was the year I tried to save money by using one of these outfits, and the service technician failed to notice a belt that was about to break. Now I stick with a mechanic I know and trust (more on that later).

Have a fill-up routine. Pop the hood and check your oil. While you're there, wipe the battery clean with a damp towel and check for corrosion, cracks or bulges. Once you're done, check your tire pressure. (Use a digital gauge, which is more accurate; you can find them for less than $20. I found one that talks, which is completely unnecessary but kind of cool.) You don't have to do this every single fill-up, but shoot for every other time.

Find a good mechanic or become one. Our current mechanic won our hearts by scoffing when we suggested fixing the gas gauge. It was an expensive repair, he explained, and unnecessary if we just reset the trip odometer at every fill-up. When the trip odometer neared 200 miles, we headed for a gas station. We trust him to let us know when a repair is necessary or smart, and his fees are reasonable (the My Car feature has a calculator to help you check these things).

Don't keep up with the Joneses

Do a walk-around. While studying for my pilot's license, I was taught to do a "walk-around" -- a careful inspection of the plane's exterior to look for potential problems -- before climbing into the cockpit. Doing the same with the Explorer helped me spot flat tires, fluid leaks and the SpongeBob SquarePants stickers my daughter liked to sneak onto every possible surface. A simple walk-around also can help you avoid running over anything that's been left behind your car, from someone's bike to (heaven forbid) someone's kid.

Drive defensively. Your car will never be the same after it's been in a major accident, and its useful life can be shortened significantly (assuming it's not already totaled). So slow down, expect other drivers to be idiots, and don't be one yourself. That means hanging up when you drive.

Keep it clean and waxed. I was less meticulous about this than my husband was when the Explorer was his primary car, but regularly removing the grime helps protect the exterior, as does a regular paste wax (as soon as water stops beading on the paint, it's time to wax again). If you live in a cold-weather climate, it's important to regularly sluice off the road salt, sand and slush to prevent rust and other damage.

Refuse to care what other people think. I'm convinced that many, if not most, cars are traded in before their time simply because people become embarrassed about driving them. I chose to turn that thinking on its head by taking perverse pride in showing up with the oldest car at any restaurant, party or local event I attended. My motto was: "Laugh all you want. It's paid for. Is yours?"

Know when to fold. Consumer Reports says you should ditch a car when the cost of a repair exceeds its fair market value. For me, the bright line for retiring a car is when I can no longer trust it to get me from Point A to Point B. If one repair follows another, maybe it is better to bail, but it takes a lot of repairs to outweigh the cost of car payments (or the interest we'd lose by using savings to pay cash for the next car).

I might still be driving The Beast to this day if it hadn't been for the recession and phenomenal car deals that suddenly became available. After 16 years, we'd already owned the car six years longer than we'd planned, and we knew we'd have to replace it soon. So we pulled the trigger.

The Beast was passed along to some friends who wanted a bigger vehicle for in-town driving. We found a year-old Volvo C30 for my husband, and I once again inherited the car he'd been driving -- a nicely maintained (of course!) Volvo wagon. I have to say, it's nice having a working gas gauge again.

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.