You might have a roommate or family member on your policy that no longer drives your vehicles. Or maybe you have a vehicle on your policy that is no longer being driven. Making sure driver and vehicle information is up to date may save you money. Keep in mind, if you do go down to just one car on your policy, you will lose the multi-vehicle discount.
The minimum coverage defined by German law for car liability insurance / third party personal insurance is €7,500,000 for bodily injury (damage to people), €500,000 euro for property damage and €50,000 for financial/fortune loss which is in no direct or indirect coherence with bodily injury or property damage. Insurance companies usually offer all-in/combined single limit insurances of €50,000,000 or €100,000,000 (about €141,000,000) for bodily injury, property damage and other financial/fortune loss (usually with a bodily injury coverage limitation of €8-15,000,000 for each bodily injured person).
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.