What he said. I have four properties, a car and an umbrella policy. Because of the umbrella policy, I am stuck with a limited array of companies to choose from. Most places want you to have all the policies with them, or at least higher coverage on your car and home if you insure elsewhere.
When you have rental property, it's even worse. Add to that the need to find an affordable earthquake policy, and you can understand why it's a day long endeavor getting quotes to compare when shopping for insurance every year or so to make sure I'm getting the best deal.