Typically, insurance companies check the driving records of their customers every few years, or when a potential customer is applying for an insurance policy. If the insurance company learns that one of their customers has been convicted of a DUI, the insurance company will most likely raise the customer's rates or cancel the insurance policy all together.
If the company decides to allow the driver to continue with the policy, the driver will probably be labeled as high risk, which may raise the premium drastically. In some cases the increase may be as high as three times the price of the pre-conviction cost. In most cases the driver will need to file proof of insurance (form SR 22) with the Department of Motor Vehicles for up to five years. The insurance company will have to file various documents with the DMV, as well as inform the DMV if the insurance policy is cancelled.