If your son, daughter, wife, husband or any other policyholder on your cover makes a claim, or a claim is made against them, while they're driving their own car it won't affect any of the other policyholders' No Claims Bonus. However, if they have an accident in your car (which you are policyholder for) then your No Claims Bonus will be affected, but not for the other cars.
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.
In case there are any changes that need to be made in the policy such as address change or any particular changes regarding the automobile or its usage, it could be done by an endorsement by the insurance provider. You need to submit a letter to your insurance provider along with the proof of the changes so that you could obtain the endorsement. There are few endorsements that might charge an extra premium from you.
The insurance certificate or cover note issued by the insurance company constitutes the only legal evidence that the policy to which the certificate relates satisfies the requirements of the relevant law applicable in Great Britain, Northern Ireland, the Isle of Man, the Island of Guernsey, the Island of Jersey and the Island of Alderney. The Act states that an authorised person, such as a police officer, may require a driver to produce an insurance certificate for inspection. If the driver cannot show the document immediately on request, and evidence of insurance cannot be found by other means such as the MID, then the Police are empowered to seize the vehicle instantly.
Comprehensive insurance covers all of the above and damage to the vehicle caused by the driver themselves, as well as vandalism and other risks. This is usually the most expensive type of insurance. It is custom in the UK for insurance customers to refer to their Comprehensive Insurance as "Fully Comprehensive" or popularly, "Fully Comp". This is a tautology as the word 'Comprehensive' means full.
It’s important to note that every company considers credit very differently, and even among insurers this factor fluctuates by state. For example, NerdWallet’s 2019 car insurance rate analysis indicates that while State Farm charges higher rates for poor credit in many states, it doesn’t seem to do so in Maine. Similar variations are true for many other companies as well.
Minimal insurance policies cover only third parties (including the insured person and third parties carried with the vehicle, but not the driver, if the two do not coincide). Also the third parties, fire and theft are common insurance policies, while the all inclusive policies (kasko policy) which include also damages of the vehicle causing the accident or the injuries. It is also common to include a renounce clause of the insurance company to compensate the damages against the insured person in some cases (usually in case of DUI or other infringement of the law by the driver).
To initiate the process, insured is required to submit a detailed estimate of loss to the insurance company. Independent automobile surveyors with engineering background are given the task of assessing the reason and extent of loss. They carefully inspect the damaged vehicle and submit their survey report with the insurance company who will review and examine it in accordance with the recommendations mentioned therein The usual practice is to authorize repairs with the repairer to whom letter is issued in this regard.
Providers can also offer sub-divisions of auto repair insurance. There is standard repair insurance which covers the wear and tear of vehicles, and naturally occurring breakdowns. Some companies will only offer mechanical breakdown insurance, which only covers repairs necessary when breakable parts need to be fixed or replaced. These parts include transmissions, oil pumps, pistons, timing gears, flywheels, valves, axles and joints. 
The cheapest car insurance, period, will likely carry the minimum coverage required in your state. In most states, this is liability insurance only, which covers property damage and medical bills for others due to accidents you cause. Some states also require uninsured and underinsured motorist coverage, which pay for your injuries or damage if an at-fault driver doesn’t have enough insurance.
Vehicles kept in the UK must now be continuously insured unless a Statutory Off Road Notification (SORN) has been formally submitted. This requirement arose following a change in the law in June 2011 when a regulation known as Continuous Insurance Enforcement (CIE) came into force. The effect of this was that in the UK a vehicle that is not declared SORN, must have a valid insurance policy in force whether or not it is kept on public roads and whether or not it is driven.
While most of us are eager in availing no-claim bonuses (a discount in premium at renewal if no claim is made during the policy term), but we hardly pay attention towards other smaller discounts which can add up to a substantial amount. All comprehensive insurance plans offer reward for good claim history, with a discount which could be 50% of the premium.