Image: Car Accident © Stockdisc, Corbis

Many people consider auto insurance only when they're shopping for a new car. But drivers can save a lot of money by shopping for a new policy at other times.

If you've had some lifestyle changes, it may mean that you're eligible for cheaper and better coverage, says Christopher Brassard, the executive vice president of the Ten Eyck Group, an insurance agency in Albany, N.Y. "You could get a better price with certain carriers," he says.

According to the pros, here are five reasons to shop for a new policy:

1. Your credit scores are significantly lower or higher than when you first purchased your policy.

Many national car insurance companies consider your credit scores when they determine an auto insurance premium. They may give a higher rate to people with lower scores, says Eric Poe, the chief operating officer of Citizens United Reciprocal Exchange, an auto insurance company in Princeton, N.J.

"If your credit score is low but you're a good driver, you may find a better rate with a company that weighs other factors more heavily, such as your driving record," Poe says.

He suggests finding such a company by contacting your independent insurance agent or state department of insurance.

Remember, credit score issues don't affect only people with debt payment problems. Even borrowers with good credit can see their scores drop if they authorize multiple credit inquiries, Brassard says. Those authorizations could occur for a number of reasons, such as shopping for a new mortgage, buying furniture on a financing plan or opening a credit card account.

Brassard notes that if your credit rating decreases right before your auto insurance comes due for renewal, and your insurance company takes the new rating into account, the lower scores could mean a higher premium on the next insurance cycle.

"Timing can be an issue," he says.

On the other hand, if your credit scores have improved substantially since you purchased an auto policy, you may find a better rate with an insurance company that considers credit scores when determining rates.

2. You just got laid off, or you've started working from home.

Let an agent know if the number of miles on your commute has dropped significantly. Rates may drop if you're driving less, Poe says. If not, shop around for a company that has a lower premium.

The exact cutoff point for a low-mileage driving discount depends on the state you're in, Poe says. For example, in New Jersey, drivers who commute less than three miles per day in one direction may have their cars rated for "pleasure use." This gives the driver the same rate as someone who doesn't commute to work, which generally is the lowest rate, Poe says.

3. You're in the middle of a long-term car lease or loan.

Car loans have gotten longer in recent years.

"I've seen some places advertising 60- and 72-month car loans," Brassard says.

Such extended finance terms lower monthly payments but leave you financing most of the vehicle's value. You run the risk of becoming "upside down" on the loan, or owing more money on the car than it's worth, Brassard says.

This may not seem like a problem if the vehicle is in good condition and you're making timely payments. But if you get into an accident and the car is totaled, the insurance company will probably pay out only the vehicle's market value. If that amount is less than what you owe, you could be stuck with an unpaid loan and no working car.

One solution to this problem is to shop for gap insurance, which covers the gap between the insurance company payout and what is owed on the loan, Brassard says.

Many leasing companies, as well as some banks and insurance companies, offer gap coverage, he says. Brassard adds that some auto insurance companies may also offer a replacement-cost endorsement that would pay for the replacement cost of the covered vehicle.