You’ll notice that none of that liability coverage pays for your car or injuries, nor for any injuries your passengers sustain if you cause a wreck. This is why many people — particularly those whose car isn’t yet paid off — want “full coverage” car insurance. This isn’t actually a type of coverage, but instead typically refers to policies that include liability coverage, plus comprehensive and collision coverages.
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. 
Another important factor in determining car-insurance premiums involves the annual mileage put on the vehicle, and for what reason. Driving to and from work every day at a specified distance, especially in urban areas where common traffic routes are known, presents different risks than how a retiree who does not work any longer may use their vehicle. Common practice has been that this information was provided solely by the insured person, but some insurance providers have started to collect regular odometer readings to verify the risk.
In 1998, the Progressive Insurance company started a pilot program in Texas, in which drivers received a discount for installing a GPS-based device that tracked their driving behavior and reported the results via cellular phone to the company. The program was discontinued in 2000. In following years many policies (including Progressive) have been trialed and successfully introduced worldwide into what are referred to as Telematic Insurance. Such 'telematic' policies typically are based on black-box insurance technology, such devices derive from a stolen vehicle and fleet tracking but are used for insurance purposes. Since 2010 GPS-based and Telematic Insurance systems have become more mainstream in the auto insurance market not just aimed at specialised auto-fleet markets or high value vehicles (with an emphasis on stolen vehicle recovery). Modern GPS-based systems are branded as 'PAYD' Pay As You Drive insurance policies, 'PHYD' Pay How You Drive or since 2012 Smartphone auto insurance policies which utilise smartphones as a GPS sensor, e.g. . A detailed survey of the smartphone as measurement probe for insurance telematics is provided in 
Yes, you surely can avail the NCB if you change your insurance provider at the time of renewing the policy. All you would need to do is producing a proof of the earned NCB from your current insurance provider. You can produce the original copy of your expiring policy and a certification that you haven’t filed any claim for the (expiring) insurance plan. A renewal notice or a letter stating that you’re entitled to the NCB from your previous insurance provider can be a proof for this.
Those not exempted from obtaining insurance must obtain a certificate of insurance from their insurance provider, and display a portion of this (an insurance disc) on their vehicles' windscreen (if fitted). The certificate in full must be presented to a police station within ten days if requested by an officer. Proof of having insurance or an exemption must also be provided to pay for the motor tax.
Liability auto insurance protects you from that worst case scenario by providing a cushion between your assets and the amount you’re on the hook for. For this reason, choosing the right auto liability limits is the most important part of your car insurance quote comparison. NerdWallet typically recommends having at least as much liability coverage as your net worth.