My suggestion would be to make a trip to the library and look up your car in the Consumer Reports car information available there. I was able to look up my car and see what the most common repairs were for it. You will also find other books, including Chiltons repair books, that tell you how to fix your car. Your car manual will tell you what repairs need to be done at certain mileage points, like changing the timing belt etc. You need to also factor in how much these average repairs would cost you.
Insurance companies exist to make money and they are VERY successful at it.
I would do my homework thoroughly before giving them my money as the company will have to turn a profit somehow. My husband is a professional auto mechanic, yet we have extended warrantees on both of our vehicles, a car and a truck. Many people wonder why we would need these, since he can provide the labor himself and also gets parts a bit cheaper through his employer, a new car dealership. The car was out of the factory warranty but the extended warranty was in place. The warranty covered this, including the 2 days of labor and a rental car to drive.