Know when to cut coverage. Don’t strip away coverage just for the sake of cheaper insurance. You’ll need full coverage car insurance to satisfy the terms of an auto loan, and you’ll want it as long as your car would be a financial burden to replace. But for older cars, you can drop comprehensive and collision coverage, which only pay out up to your car’s current value, minus the deductible.
Under the cents-per-mile system, rewards for driving less are delivered automatically, without the need for administratively cumbersome and costly GPS technology. Uniform per-mile exposure measurement for the first time provides the basis for statistically valid rate classes. Insurer premium income automatically keeps pace with increases or decreases in driving activity, cutting back on resulting insurer demand for rate increases and preventing today's windfalls to insurers, when decreased driving activity lowers costs but not premiums.
Soon after the introduction of the Road Traffic Act in 1930, unexpected issues arose when motorists needed to drive a vehicle other than their own in genuine emergency circumstances. Volunteering to move a vehicle, for example, where another motorist had been taken ill or been involved in an accident, could lead to the "assisting" driver being prosecuted for no insurance if the other car's insurance did not cover use by any driver. To alleviate this loophole, an extension to UK Car Insurances was introduced allowing a Policyholder to personally drive any other motor car not belonging to him/her and not hired to him/her under a hire purchase or leasing agreement. This extension of cover, known as "Driving Other Cars" (where it is granted) usually applies to the Policyholder only. The cover provided is for Third Party Risks only and there is absolutely no cover for loss of, or damage to the vehicle being driven. This aspect of UK motor insurance is the only one that purports to cover the driving of a vehicle, not use.
 Availability varies. Enrollment discount applies during data collection; final discount is calculated on driving behavior and could be zero. Discounts do not apply to all coverage elements; actual savings vary by state, coverage selections, rating factors and policy changes. Final discount applies at the next policy renewal and remains until drivers or vehicles on the policy change.
When the premium is not mandated by the government, it is usually derived from the calculations of an actuary, based on statistical data. The premium can vary depending on many factors that are believed to affect the expected cost of future claims. Those factors can include the car characteristics, the coverage selected (deductible, limit, covered perils), the profile of the driver (age, gender, driving history) and the usage of the car (commute to work or not, predicted annual distance driven).
Several jurisdictions have experimented with a "pay-as-you-drive" insurance plan which utilizes either a tracking device in the vehicle or vehicle diagnostics. This would address issues of uninsured motorists by providing additional options and also charge based on the miles (kilometers) driven, which could theoretically increase the efficiency of the insurance, through streamlined collection.