The main difference between collision and comprehensive coverage comes down to the question of what the driver controls. Collision insurance will cover events within a motorist's control or when another vehicle collides with your car. Comprehensive coverage generally falls under "acts of God or nature," or things that are typically out of your control when driving. These can include events such as a spooked deer, a heavy hailstorm, or a carjacking.
These are on the high side, but there are still instances in which they won’t be enough to fully cover you. For example, if you accidentally hit a luxury car, replacing it could easily cost more than the $25,000 legal minimum for property damage coverage. If the other driver is injured, his or her medical bills could also exceed the $30,000 bodily injury minimum fairly easily. In each case, you’d be responsible for making up the difference yourself.

One way to do this is to call the insurance company and see what the hold time is and what the service is like when you wait to speak to a representative about a general inquiry. If the hold time is 3 hours and they don’t seem like an accommodating group, you’re probably not going to want to deal with them after you just lost your house and file a claim.
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.