Normally, it is in your best interest to insure both your auto and home insurance with the same company. Generally insurance companies will give a substantial discount on your home insurance, if you also have your auto insurance with them. The discounts can range from 10% to as much as 25% or more off of the homeowners insurance.
There is also typically a discount on the auto insurance for having the home insurance with the same company. Although, the discount on the auto insurance is not normally as large as the discount applied on the homeowners insurance. As a result, you will normally have significant savings by having both policies insured with the same company.
In addition, it tends to be more convenient to have one place to call with all of your questions and if your agent handles all of your insurance coverage they are normally in a better position to assess your needs and make coverage recommendations.
