Having a car accident can be an awful experience. Even if no one was injured during the car accident, the affect it can have can last weeks if not months afterwards. Many people reply on their car to get them to and from work or to take and pick the children / grandchildren etc. up from school. Suddenly finding yourself without a car can cause a nightmare.
Some insurance companies will offer you a courtesy car but often this is a group a car which is a small car such as a KA or Corsa. If you need a bigger car then you may be able to pay for an upgrade otherwise you will need to look at hiring a vehicle. This is an additional expense that you may not be able to claim back for. If your car is written off then usually the courtesy car is needed back the same or the following day leaving you very little time to source a new one. Always be sure to check the cover you have when taking out an insurance policy.