Another Example of Insurance Strategies

"I have a single policy cover all my SFH and Duplexes:
Actually it is more of a commercial type blanket policy, extended to all my properties, anytime if I buy a home, it is automatically covered, each property has a building liability of 500k, and a 2m commercial umbrella as backup."

Question:

"How do you get that? Is it cheaper when comes down to each property? Does the premium increase every time when you add a new property?"

Answer:

"1. it is a custom tailored policy.
2. yes a bit cheaper.
3. yes."