If your vehicle had damage to it prior to the accident, it can be difficult to determine exactly what portion of the damage was caused by the accident itself. For example, if your car has a mechanical problem, the insurance company may claim that it existed prior to the accident if some evidence indicates that there was substantial wear and tear. Therefore, it is important that you prove the connection between the auto accident and the damage you are claiming. Ordinarily, mechanics and collision repair personnel can help to prove the age of body damage or the cause of a mechanical failure. They can assist to convince the insurance company that the auto accident caused the damage you are claiming.