Multi car insurance is designed for households with more than one car, and you can usually cover up to a maximum of five cars on one policy. You can think of it as a family car insurance policy, where each additional vehicle on the policy earns a further multi car discount from the insurer. While some insurers will only cover cars registered to the same address, the best multi car insurance policies will also allow you to cover cars driven by your immediate family, even if they live elsewhere.
Auto insurance is financial protection, and not just for the investment you made when you bought your car. After a really serious accident, bills for damage and injuries can easily reach into hundreds of thousands of dollars. If you happen to cause such a wreck, the victims could sue you. In the worst case scenario, assets such as your savings and home could be seized.