Newspaper columnists are supposed to have bees in their bonnets, and if you’ve read my preachings for very long, you’ll know my chronic gripe involves cars.

Buy a modest, used vehicle, pay cash and keep it until the engine falls out — that has been my mantra.

Of course, when I desperately needed a new pickup a few years ago, I ended up with a brand new, full-sized Ford F-150 instead of the smaller Ranger. And I took out a three-year loan, to boot.

Hypocrisy? Not really. It’s just that the year-end deals offered in September and October can turn a sound strategy on its head.

The big trucks didn’t cost much more than the small ones, the used ones didn’t offer much savings. And if the car maker is offering loans at 1.9 percent, it can pay to borrow and use the cash for an investment instead.

So, with that confession off my chest, here are a few pointers on handling car issues during this change-of-model season:

• New versus used. At least consider a good used vehicle. All cars and trucks lose value each year, but the biggest losses come in the first few years. Buying a new car every year or two means taking an enormous beating from depreciation.

Buy a 3- or 4-year-old car and keep it for seven or eight years.

• The Whopper Test. This is a value-assessment test I devised a while back for comparing alternative purchases. It’s based on my belief that not many expensive restaurant meals are much better than an inexpensive Burger King Whopper. The $40 filet mignon is not 10 times better than the $4 burger.

With cars, it means deciding whether spending $10,000 more to get a top-of-the line SUV will really bring $10,000 worth of additional happiness, utility or status — whatever it is you’re looking for in the next vehicle.

• Buy, don’t lease. Leasing offers headache-free ownership, since you’re always on warranty. But lease payments are primarily based on the high depreciation the new vehicle will go through over the two, three or four years of the lease. So the serial leaser is condemned to an endless financial battering and never gets free of monthly payments. Add up the total cost of each alternative: Buying is cheaper, especially if you keep your car for seven, eight, 10 years — as long as possible.
• Weigh the rebate. Dealers sometimes offer thousands in rebates, or low-interest financing, but not both. Obviously, if you can get cheap financing elsewhere, it makes sense to take the rebate and have it both ways. But if that’s not an option, you need to figure which choice makes the car cheaper over the long run.

Calculations by Capital One bank show that over three years, the buyer of a $20,000 vehicle would save more than $1,100 by opting for a $2,000 rebate and 3.99 percent loan rather than no rebate and zero-percent financing. But changing any of the figures could tip the balance the other way.

Tally the monthly payments under each option, then add the result to the cash you’d lay out up front. You can evaluate the choices with the free calculator at the Web site of Edmonds.com, the vehicle data service, at www.edmunds.com.

There’s another good one at www.bankrate.com/brm/calc/rebatecalc.asp, the site of rate-monitoring company Bankrate.com.

• Also consider paying cash. This boils down to comparing the interest rate on the best loan you can get with the rate of return you could earn by saving or investing your cash. If you can borrow at, say, 4 percent and can invest at 6 percent, you can make 2 percent by borrowing the car money and investing your cash. These days, of course, there’s no guarantee you will make 6 percent, so you have to consider your willingness to take risks.
• Be sure to look at financing alternatives other than those offered by the car dealer. You may get a lower rate at a bank or credit union.

Sometimes there are good rates on home-equity loans, which use your home as collateral for the loan. Interest paid on home equity loans is deductible on the federal income tax return, so a 6 percent loan may really cost you only 4.5 or 5 percent.

Be careful, though. Buying a car with a five- 10-, or 15-year home equity loan can mean paying a lot more in interest over the term of the loan than you would with a three- or four-year car loan, even if the home equity rate is lower.