Regardless of the type of car you drive or where you drive it, by owning and operating a vehicle and driving it on public roads, your car is vulnerable to all types of losses and damages, both to yourself and to others on the road and their property. Though you’re probably most concerned with accidents, your vehicle can also be damaged by acts of weather such as falling tree limbs or monster-sized hail, vandalism or even invaded by creepy crawlers, especially if you park outside or on the street.
While an “insured vehicle” may include a friend or neighbor’s vehicle or a rental car, if the vehicle was available for regular use, it might be excluded. A “replacement” vehicle will probably be covered, but in some cases only under circumstances where the insured’s vehicle cannot be operated for some specific reason, such as a repair. Coverage might not follow anyone if the insured is driving a vehicle other than a “private passenger vehicle not owned and listed on the insured’s policy.” There really is no such thing as a standard auto policy anymore and coverage for non-owned autos will be different under some policies and non-existent under others.
Once you know the approximate value of your car and the cost to carry collision coverage, then you can make an informed decision about purchasing that coverage. Many people find that it's a good idea to cover newer cars, but as cars get older, their values decrease, and you might consider omitting or dropping this coverage to save money on your auto insurance.
Comprehensive car insurance covers damages from an "act of God," or events that are not caused by a car driving into something else. An "act of God" can include things like damage from a heavy tree branch falling on your car. Since you have no control over when or why a tree branch would fall on your car, this kind of accident would be covered under your comprehensive policy.