When insured parties experience a loss for a specified peril, the coverage entitles the policyholder to make a claim against the insurer for the covered amount of loss as specified by the policy. The fee paid by the insured to the insurer for assuming the risk is called the premium. Insurance premiums from many insureds are used to fund accounts reserved for later payment of claims – in theory for a relatively few claimants – and for overhead costs. So long as an insurer maintains adequate funds set aside for anticipated losses (called reserves), the remaining margin is an insurer's profit.
Let's use the aftermath of a major storm to illustrate the differences between collision and comprehensive. Within that storm, let's consider two hypothetical events: First, a heavy telephone pole was blown down and fell on your truck, or second, you swerved to avoid a falling tree and wound up crashing into a guardrail. In the first event, you couldn't control when or why a tree fell 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 guardrail. This makes it a collision, and collision insurance pays for the damages.