If you haven't shopped around for a better auto-insurance rate, you should. Like, now.

Nonprofit consumer group Delaware Valley Consumers' Checkbook magazine and Checkbook.org compared prices charged by the Philadelphia area's largest auto insurers and found that most area drivers will save $500 or more a year by making a better auto-insurance choice. Many will save $1,000 or more.

For the next month, Checkbook is offering free access to its ratings of auto-insurance companies to Inquirer readers through this link: www.checkbook.org/inquirer/auto-insurance.

Here are the types of savings that Checkbook found to be available to most area families:

A couple with two cars living in Montgomery County with clean driving records would pay $895 with GEICO, $1,082 with Progressive, or $1,138 with Esurance, compared with $1,962 with Allstate, $1,984 with State Farm, and more than $3,000 with Donegal or Penn National.

If that couple moved to Cherry Hill, they would pay $1,160 with Esurance, $1,197 with Palisades, or $1,307 with GEICO, compared with $3,000 or more with AAA, Farmers, or State Farm.

If they needed to add a teenage son to their policy, they would pay $1,880 with Progressive or $2,045 with GEICO, compared with $3,864 with State Farm and more than $4,000 with several other companies.

Although it's a bit of a pain to shop for auto insurance, most consumers would agree that spending a few hours to save $500, $1,000, or more every year is worth the effort.

Note that you don't have to wait until your current policy term expires to take advantage of the savings you'd get from a switcheroo. When you switch to a lower-priced company, your old insurance company will refund the unused share of your premium.

You also don't have to forsake service for a better rate. In addition to comparing the prices offered by local insurance companies, Checkbook asked insurance customers and auto-body shops to rate insurers for their claims-handling service. Checkbook's ratings reveal that some highly regarded companies offer low rates.

You might think that if you've been driving for many years without an accident and with few speeding tickets, insurance companies will offer you their best rates. Unfortunately, that's not necessarily the case. Insurers increasingly are offering their best rates only to customers who meet criteria that have nothing to do with their driving histories.

For example, most companies offer their lowest rates only to customers who have excellent credit scores and are college graduates and homeowners. And insurers are increasingly using secretive methods to calculate rates. With most companies, Checkbook found, your credit score and other information may matter more than your driving record.

The appropriateness of using credit histories and other similar data in setting insurance rates is a hotly debated topic among the insurance industry and consumer groups. Companies clearly charge far higher rates to customers with poor credit scores than they do to people with good scores.

Checkbook found, for example, that for one driver profile of a 38-year-old female driver with "excellent" credit, she would pay, on average, $936 more per year if she had a "fair" credit score. Compare that increase with the $775 penalty for having a recent at-fault accident or the $595 penalty for having two recent speeding tickets.

Checkbook's comparison tool will help many families identify the lowest-cost companies for them, but because we found that small differences in policyholder characteristics, many of which have nothing to do with driving records, can have big effects on some companies' premiums, be sure to check the rates yourself.

You want to buy enough coverage to protect yourself - but not so much that you're wasting money.

Avoid common car-insurance mistakes by doing the following:

Make sure you maintain the highest deductible amount with which you're comfortable.

Be vigilant that your coverage doesn't lapse.

Consider dropping collision coverage when your vehicle's value drops below $3,000 or so.

When shopping for coverage, find out how much more it will cost to raise the limits beyond standard coverage. It is usually inexpensive to increase limits for liability coverage above the standard amounts.

Carefully consider the extras. Some optional coverages aren't worth much, but companies charge a lot for them.

For repairs, insist on using a shop you can trust - as long as it charges reasonable rates. At Checkbook.org, you'll also find ratings of area auto-body shops for quality and price.

Delaware Valley Consumers' Checkbook magazine and Checkbook.org is a nonprofit organization with a mission to help consumers get the best service and lowest prices. It is supported by consumers and takes no money from the service providers that it evaluates.

You can access all of Checkbook's ratings of car-insurance companies free of charge until Dec. 7 at www.checkbook.org/inquirer/auto-insurance.