An insurance underwriter's job is to evaluate a given risk as to the likelihood that a loss will occur. Any factor that causes a greater likelihood of loss should theoretically be charged a higher rate. This basic principle of insurance must be followed if insurance companies are to remain solvent.[citation needed] Thus, "discrimination" against (i.e., negative differential treatment of) potential insureds in the risk evaluation and premium-setting process is a necessary by-product of the fundamentals of insurance underwriting. For instance, insurers charge older people significantly higher premiums than they charge younger people for term life insurance. Older people are thus treated differently from younger people (i.e., a distinction is made, discrimination occurs). The rationale for the differential treatment goes to the heart of the risk a life insurer takes: Old people are likely to die sooner than young people, so the risk of loss (the insured's death) is greater in any given period of time and therefore the risk premium must be higher to cover the greater risk. However, treating insureds differently when there is no actuarially sound reason for doing so is unlawful discrimination.

Let's use the aftermath of Superstorm Sandy as an example to illustrate the differences between collision and comprehensive. Within that storm, let's consider two events that might have happened: 1) a heavy tree branch fell on your car, or 2) you swerved to avoid a falling tree branch and wound up crashing into a tree. In the first event, you had no control over when or why a tree branch would fall on your car. This kind of accident would get reimbursed under your comprehensive policy. In the second situation, you were driving the car and ultimately swerved into the tree, which makes it a collision, and collision insurance therefore pays for the damages. Events like the hypothetical ones stated above are why it's important to differentiate between the two types of coverage.

Auto insurance will generally cover a driver from any state as long as he has the insured’s permission to operate the vehicle. However, this isn’t always the case. In all instances, when someone else operates the insured’s vehicle, the auto coverage and policy terms may vary greatly depending on the carrier and insurance options selected by the insured. That said, if an insured is driving a company/commercial vehicle which has Med Pay/PIP coverage, that coverage is usually primary over the driver’s personal auto policy, which will be secondary in terms of coverage. There are some exceptions.
In many cases, the legal minimum insurance won’t be enough to cover costs if you cause an accident. If you total someone’s luxury car, for example, their repair costs could easily exceed a $25,000 ceiling. Any damage that surpasses your limits has to come out of your own pocket. That’s why for most drivers it’s wise to select higher limits, such as 100/300/50.

When the policy of the vehicle owner and the policy of the permissive user have different limits, the matter becomes even more complicated. If the damages caused by the permissive user’s negligence exceed the owner’s liability limits, the policy of the permissive user might be tapped as secondary coverage, but usually only where the permissive user’s liability limits are higher than the owner’s liability limits.
Policies typically use vague language when referring to acts of terrorism, but they are generally insured by the comprehensive portion of your policy. For example, if there is an act of terror and you need to make a claim on your car, that can only be made if you have comprehensive coverage. Since some circumstances are out of our control, comprehensive insurance is certainly important to have in your policy.