when does a car become a write off
 

does a car become a write off when it costs more then the car is worth to repair or when it goes over a certain percentage of its worth? say 75% of its book price?

It varies between insurers, the term usually used is "beyond economical repair", which means different things to each insurer. The insurer would also add in costs such as hire cars and balance that up against a quick cash settlement.

Where the car is new and on a new for old basis, the insurer will get a preferential price on a new car so a new car may get written off at a seemingly low price.

I think they work at 55-65% of the value of the car as the guide. If the assessor gets a nice drink at Christmas, from the garage that are holding the car, he will do his best to get the car repaired.

50-60 we work at