The value of a car is taken into account for third party, fire and theft and for comprehensive insurance. What you have the car insured for, however, is not always what the insurance company will pay out in the event of a claim. In the event of the car being a write-off, the insurance company will only pay out what it feels the car is worth, which, more often than not, is less than the car is actually insured for. There is very little to gain by over-insuring a car and, equally, you should not under-insure it either.